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This study aims to identify challenges as well as entry points for governments in Southeast Asia and elsewhere to reduce the risk from agricultural pesticides by comparing levels of pesticide use, pesticide regulation, and farm-level practices in Cambodia, Laos, Thailand and Vietnam. We identified three main challenges to pesticide risk reduction: (a) the rapid expansion of pesticide trade—in terms of total volume, number of products and number of selling points, combined with a weak regulatory and enforcement capacity; (b) a high level of satisfaction among farmers with pesticides combined with low levels of risk awareness, lack of technical know-how about integrated pest management (IPM), and general unavailability of biocontrol agents; and (c) no regular monitoring of pesticide risk, which makes it difficult for legislators, regulators, farmers and consumers to make rational decisions. The study highlights several examples countries can emulate, including the introduction of a pesticide tax in Vietnam, the pesticide registration system in Thailand, regular training of pesticide retailers in Thailand and Vietnam, and product certification.

The cotton aphid (Aphis gossypii) is one of the major pests of okra. Eleven okra varieties collected from farmers' fields in Cameroon and four aphid-resistant accessions from The World Vegetable Center (AVRDC, Asian Vegetable Research and Development Center) were evaluated from October 2012 to March 2013, and another seven aphid-resistant accessions from AVRDC were evaluated from March to July 2013 at AVRDC's Nkolbisson station, Yaounde, Cameroon. Accessions selected from these trials were screened in an advanced confirmatory screening in autumn (October–December) 2013 in Shanhua, Taiwan. Results showed that none of the farmers' landraces were resistant to aphids. Two accessions (VI041210 and VI033824) with the lowest aphid populations had the highest trichome density. Analysis of various phytochemicals in selected okra accessions revealed that higher nitrogen and potassium levels made the okra accessions susceptible to aphids during the reproductive stage of the plants. Similarly, the total phenol conten...

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is native to South America but has invaded the Afro-Eurasian supercontinent where it is currently the most devastating invasive arthropod pest of tomato. As a part of the first classical biological control programme against T. absoluta in Africa, a larval parasitoid, Dolichogenidea gelechiidivoris Marsh. (Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta was imported from Peru into the quarantine facility of the International Centre of Insect Physiology and Ecology, Kenya. We report on the host larval preference of D. gelechiidivoris and the host suitability, and the parasitoid’s reproductive strategy, including lifetime fecundity and egg maturation dynamics. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post eclosion. The females of D. gelechiidivoris survived 8.51 ± 0.65 d and produced 103 ± 8 offspring per female at 26 ± 4 °C (range: 24 to 29 °C) and 50–70% relative humidity (RH) with males present and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The potential intrinsic rate of natural increase was 0.18. This study shows that D. gelechiidivoris is a potential biological control agent of T. absoluta and should be considered for release in Kenya and across Africa following host specificity testing and risk assessments.

Insect pests pose major challenges to optimum productivity of amaranth in Africa and Asia. The use of insecticides is the main control strategy, but is expensive and may pose health and environmental concerns, especially if proper care is not taken. Host plant resistance offers a cheap and sustainable pest management alternative. Open field experiments were conducted during two cropping seasons in 2016 and 2017 to screen 35 amaranth accessions and lines for resistance to leaf-webbers and stem weevils. The diversity (H) of lepidopteran defoliators and their parasitoids on each accession ranged from 0.00 to 1.57 and 0.00 to 1.65, respectively during the long rainy season and from 0.00 to 1.58 and 0.00 to 1.01 in the short rainy season. Accessions VI036227, RVI00027, VI054569, VI033487, VI044432, VI048076, VI049639, VI049530 and VI049698 had high levels of pest resistance with significantly lower infestations (≤ 11.11 ± 2.14%) and damage (≤ 68.06 ± 3.90%) by leaf-webbers and leaf-worms. Stem weevil infestations ranged from 68.70 ± 2.0% to 90.42 ± 1.0% during the long and short rainy seasons, respectively. Accessions VI047517-B, VI036227 and VI056563 had the least stem weevil infestations (

Incidence of vector-transmitted virus diseases and the damage caused to vegetable crops by these diseases are reported to be increasing in countries with tropical and subtropical conditions. Virus-resistant crops and an integrated approach to crop management including appropriate control of plant-virus insect-vectors could reduce the problem. However, in developing countries, such a strategy is rarely applied effectively. We surveyed 800 growers of chili, tomato and mungbean in India, Thailand and Vietnam to understand what farmers know about plant viruses, their perceptions about yield damage, the control methods they choose to apply and the perceived effectiveness of these. Farmers regarded their economic losses from pests and diseases to be very substantial. Only a minority of them knew that certain disease symptoms were probably being caused by a plant virus and even fewer knew about the role of insect vectors in its spread. Farmers mostly relied on synthetic pesticides to manage the virus disease symptoms they observed. If farmers had better knowledge about plant viruses, their insect vectors, and cost-effective, safer means of control, then use of synthetic pesticides could be reduced substantially. Building knowledge among farmers is therefore an important way to address the diseases caused by plant viruses, while the development of virus-resistant varieties and simple and effective methods of vector control offer longer-term solutions.

The insecticidal activity of Maruca vitrata (F.) multi-nucleopolyhedrovirus ( Mavi MNPV) combined with oil from neem, Azadirachta indica Juss and Jatropha curcas L. (Euphorbiaceae) was studied under laboratory and field conditions against three key insect pests of cowpea, Vigna unguiculata (L.) Walp. Second-instar Aphis craccivora Koch and Megalurothirps sjostedti Trybom nymphs, and third-instar M. vitrata larvae, all from laboratory colonies, were treated with various concentrations of one of the control agents separately or combined. Daily mortality was recorded for five days ( A. craccivora and M. sjostedti nymphs) or fourteen days ( M. vitrata ) and the larval and pupal development as well as adult emergence were assessed. Combination of Mavi MNPV resulted in a significantly higher larval mortality in M. vitrata than treatment with either virus or botanical insecticide alone at the corresponding concentrations. Larvae of M. vitrata infected with Mavi MNPV and treated with botanical oils died sooner than those infected with only one control agent. Combinations of Mavi MNPV and botanical oils produced additive or synergistic effects. No evidence of antagonistic effects was noted. In field experiments, the application of botanical insecticide and Mavi MNPV either alone or in combination was effective in reducing insect abundance over the four weeks, and preventing yield loss. In the first field season, where the M. vitrata population was higher, the combination of the virus and either of the botanical pesticides induced significantly higher yields than spraying chemical insecticide. Application of Mavi MNPV in combination with J. curcas and A. indica oil has proven to induce consistent Mavi MNPV infection in M. vitrata populations. The combined application of Mavi MNPV and botanical oils is discussed in the context of integrated pest management.

The aim of this study was to identify and develop entomopathogenic fungi as biopesticides for management of Maruca vitrata (Fabricius). Fourteen isolates of Metarhizium anisopliae (Metchnikoff) Sorokin and six of Beauveria bassiana (Bals.-Criv.) Vuill. were screened against first instar larvae of M. vitrata. The two most virulent isolates were selected and further tested for production in four liquid media. Different formulations of one isolate were evaluated against different developmental stages. Metarhizium anisopliae ICIPE 18 and ICIPE 69 caused highest larval mortality of 91 and 81%, with lethal time to 50% mortality (LT50) values of 1.8 and 1.7 days and LC50 of 1.07 dx 107 and 3.01 dx 106 conidia/ml, respectively. ICIPE 69 yielded more biomass and propagules in two liquid media than ICIPE 18. All developmental stages and adult moths were susceptible to fungal infection and horizontal transmission caused a significant reduction in fecundity. Isolate ICIPE 69 was identified as the most potent isolate for managing M. vitrata based on demonstrated efficacy against different developmental stages and amenability to production in liquid media and could be utilized as an alternative to pesticides in cowpea IPM.

Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important pulse crop in Asia, and is consumed as dry seeds and as bean sprouts. It is an excellent source of digestible protein. Bruchids [Callosobruchus chinensis (L.) and Callosobruchus maculatus (F.)] are the important pests of mungbean and cause damage in the field and in storage. Bruchid infestation reduces the nutritional and market value of the grain and renders seeds unfit for human consumption, agricultural and commercial uses. These pests are controlled mainly by fumigation with highly toxic chemicals such as carbon disulfide, phosphene, and methyl bromide, or by dusting with several other insecticides, which leave residues on the grain, thus, threatening food safety. Some plant-based extracts have been found useful in controlling bruchids, but are not fully successful due to their short-term activity, rapid degradability, and potentially negative effect on seed germination. Although some wild sources of bruchid resistance in mungbean have been reported, which have been used to develop bruchid- resistant lines, undesirable genetic linkages threaten the proper exploitation of genetic diversity from wild germplasm into commercial cultivars. Further, biotype variation in bruchids has rendered some mungbean lines susceptible that otherwise would have been resistant to the pest. Host plant resistance is a cost-effective and a safe alternative to control bruchids in mungbean and is associated with morphological, biochemical, and molecular traits. These traits affect insect growth and development, thereby, reduce the yield losses by the pests. Understanding the defense mechanisms against insect pests could be utilized in exploiting these traits in crop breeding. This review discusses different traits in mungbean involved in defense against bruchids and their utility in pest management. We also highlight the breeding constraints for developing bruchid-resistant mungbean and how can these constraints be minimized. We further highlight the importance of supporting conventional breeding techniques by molecular techniques such as molecular markers linked to bruchid resistance.

The applicability of C–H functionalization to medicinally important 2-pyridyl-based N-heterocycles suffers from severe challenges owing to the high Lewis basicity of the N-atom. This arrests catalytic activity and yields undesirable positional selectivity due to preferential chelate formation. In this regard, we report a novel palladium(II)-catalyzed arylation strategy on multiple-N-containing pyridazines by over-riding the functionalization due to a chelated palladacycle. We report a regioselective mono-arylation at the 8-position of diphenyl azolopyridazines without any ortho-C–H activation on the proximal phenyl groups. This methodology presents a broad arylation scope with uncompromised yield and positional selectivity, including the heteroarylation of N-heterocycles, which is an unprecedented feat for these types of molecules.

Okra germplasm collected from different locations around the world were screened at AVRDC (The World Vegetable Center) in 2011 and 2012 to identify germplasm resistant to the melon aphid (Aphis gossypii) for use in sub-Saharan Africa. A total of 260 okra accessions and varieties were screened (150 at AVRDC Taiwan and 110 at AVRDC Cameroon), which included four varieties commercially available in Cameroon. The experiments were conducted under natural infestation in Shanhua, Taiwan, and at Yaounde, Cameroon. Since the preliminary screening trials were conducted in Taiwan and Cameroon, the aphid populations in these two countries were compared. A total of 60 insects was used for cytochrome c oxidase I (COI) gene sequencing and phylogenetic analysis. The nucleotide sequences of all the populations showed 100 % similarity and the phylogenetic analysis confirmed the genetic similarity of A. gossypii in Taiwan and Cameroon. Results of the screening trials showed that three accessions (VI033805, VI036213 and VI051114) were resistant to A. gossypii. The basis of resistance of the three okra accessions was elucidated by studying their biochemical and biophysical properties. There was no significant difference between the susceptible and resistant okra accessions in terms of leaf tannins, free amino acids, total sugars and total phenols. Only total nitrogen was significantly different between the susceptible and the two resistant okra accessions with the lowest aphid infestation (VI033805 and VI036213). Thus, higher leaf nitrogen content seems to favour the aphid infestation on okra. For physical parameters, there was no significant difference among the accessions in trichome density of bottom and middle leaves, and leaf toughness. However, trichome density in the younger leaves of resistant VI033805 was significantly higher than susceptible VI057245. Studies on settling behaviour showed that aphids did not discriminate between the susceptible and resistant okra accessions for oviposition and feeding 72 h after release.

Vegetable legumes are important crops in tropical agriculture, but they are susceptible to a substantial number of arthropod pests and diseases. Using farm-level survey data for 240 farm households growing yard-long bean (Vigna unguiculata subsp. sesquipedalis) in Thailand and Vietnam, this study shows that the farmers' main problem is the legume pod borer (Maruca vitrata). Farmers rely exclusively on the use of synthetic pesticides to manage this pest, and no other control methods are generally applied. Small cultivated areas for growing yard-long bean (particularly in Vietnam), a high level of satisfaction with the use of pesticides and a lack of market demand for pesticide-free produce are formidable challenges to the introduction of integrated pest management (IPM). It is important to ensure that IPM methods, if adopted, do not reduce profits and that farmers are allowed to experiment with these methods while raising awareness in the general population about the risk resulting from pesticide exposure.

This study aims to confirm the potential of bio-pesticide application under field conditions in combination with chemical pesticides against the pest moth Maruca vitrata on yard-long bean. Four field trials were conducted at two locations (AVRDC East and Southeast Asia Regional Research and Training Station, and farmers’ fields in Kamphaeng Saen, Thailand) from March to May 2012 and May to August 2012. The yard-long bean pod damage by M. vitrata was significantly reduced by 23–85%, with substantial yield increases (22–190%) in Bacillus thuringiensis-based treatments in combination with cypermethrin, when compared with the untreated check. Although the combined effect of cypermethrin with Beauveria bassiana or neem-based treatments was better than the untreated check, the pod damage was still higher in these treatments, recording up to 26.87% compared with B. thuringiensis subsp. aizawai-treated plots. Based on these results, B. thuringiensis is a promising component for integrated pest management strategi...

This study aimed to understand farmers' knowledge, attitudes, and practices regarding agricultural pest management and synthetic pesticide use in Southeast Asia. Data were used from 900 farm households producing leaf mustard (Brassica juncea (L.) Czern. et Coss.) and yard-long bean (Vigna unguiculata subsp. sesquipedalis (L.) Verdc.) in Cambodia, Laos and Vietnam. Farmers heavily depended on synthetic pesticides as their main method of pest control. Most farmers were aware of the adverse health effects associated with pesticide use and covered body parts while spraying, but also considered pesticides to be highly effective and indispensable farm inputs. Farmers were largely unable to distinguish between common beneficial and harmful arthropods. Greater knowledge about this was associated with less pesticide use while greater awareness of pesticide health risks was associated with fewer observed poisoning symptoms. For the average farm and while controlling for other factors, farmers who sought advice from friends and neighbors used 45% less pesticide, but those who sought advice from pesticide shopkeepers used 251% more pesticide. Pesticide use was 42% less when a woman was in charge of pest management and 31% less when farmers had adopted biopesticides. These findings suggest relevant entry points for interventions aimed at reducing pesticide dependence.

The development of cultivars resistant to tomato fruit borer, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), are very limited in Pakistan and other parts of the world because of the lack of good sources of resistance for breeding. Insect-resistant cultivars would be beneficial to decrease the indiscriminate use of pesticides on tomato crops. Seven wild tomato accessions, including Solanum galapagense Darwin & Peralta, Solanum pimpinellifolium L., Solanum cheesmaniae (Riley) Fosberg, and a susceptible check (Solanum lycopersicum L.) (all Solanaceae), were evaluated for resistance to tomato fruit borer based on oviposition preference and feeding in the choice and no-choice bioassays. In the oviposition preference test, S. cheesmaniae (VI037240) and S. galapagense (VI063174) recorded the lowest mean number of eggs, 4.40 and 7.00 per plant, respectively. The highest mortality of H. armigera larvae (90%) was recorded on S. pimpinellifolium (VI030462) compared to the susceptible check (15%). The lowest pupal weight (89.67 mg) resulted from S. galapagense (VI063174), but it was not significantly different from the S. pimpinellifolium and S. cheesmaniae accessions. Among all tested accessions, S. pimpinellifolium (VI030462) was found to be highly resistant to H. armigera based on larval mortality, pupal weight, and pupation percentage. These results can pave the way to enhance the resistance in cultivated tomato varieties to control this notorious fruit borer. Resumen El desarrollo de cultivares resistentes al barrenador de la fruta del tomate, Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae), es muy limitado en Pakistan y otras partes del mundo debido a la falta de buenas fuentes de variedades resistentes para el fitomejoramiento. Los cultivares resistentes a los insectos serian beneficiosos para disminuir el uso indiscriminado de pesticidas en los cultivos de tomate. Se evaluaron siete accesiones de tomates silvestres, incluyendo Solanum galapagense Darwin y Peralta, Solanum pimpinellifolium L., Solanum cheesmaniae (Riley) Fosberg y un control susceptible (Solanum lycopersicum L.) (todas Solanaceae), para determinar la resistencia al barrenador de la fruta del tomate en base de la preferencia de oviposicion y alimentacion en bioensayos de eleccion y no eleccion. En la prueba de preferencia de oviposicion, S. cheesmaniae (VI037240) y S. galapagense (VI063174) recibieron el numero promedio mas bajo de huevos, 4.40 y 7.00 por planta, respectivamente, en bioensayos de eleccion y de no eleccion. La mortalidad mas alta de larvas de H. armigera (90%) se registro en S. pimpinellifolium (VI030462) en comparacion con el control susceptible (15%). El peso pupal mas bajo (89,67 mg) resulto de S. galapagense (VI063174), pero no fue significativamente diferente de las accesiones de S. pimpinellifolium y S. cheesmaniae. Entre todas las accesiones analizadas, se encontro que S. pimpinellifolium (VI030462) es altamente resistente a H. armigera en funcion de la mortalidad de las larvas, el peso de las pupas y el porcentaje de pupacion. Estos resultados pueden ser un camino para mejorar la resistencia en las variedades de tomate cultivadas para controlar este notorio perforador de frutas. Key Words: tomato fruitworm; wild species; resistance; oviposition; antibiosis; mortality View this article in BioOne

The legume pod borer (Maruca vitrata) is a major destructive insect found on the yard-long bean, causing serious damage from the flowering stage. Because growers mostly rely on synthetic pesticides to control this insect, it has developed resistance to some pesticides. Information on the efficacy of bio-pesticides against this pest in Thailand is scarce. This study was conducted to evaluate the effects of selected bio-pesticides against M. vitrata. Among six commercially available bio-pesticides, only Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai were found to be more effective against M. vitrata under laboratory conditions, while neem was least effective. In a field trial undertaken between June and September 2011, both B. thuringiensis formulations significantly reduced pod damage compared with untreated plots of the yard-long bean. A similar efficacy pattern was observed during the second field trial between October 2011 and January 2012. These results suggest that B. thuringiensis formulations could become important components in an integrated pest management strategy for controlling M. vitrata on the yard-long bean in Thailand. However, the results of the current study imply the need for additional field trials with combinations of microbial, botanical, and chemical pesticides rather than a single bio-pesticide per treatment in the management of M. vitrata.

The parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) has been introduced into Benin by the International Institute of Tropical Agriculture (IITA-Benin station) from Taiwan in an attempt to control the cowpea pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae), a serious pest of flowers and pods of cowpea Vigna unguiculata Walp. (Leguminosae: Fabaceae). Both the pest and its parasitoid are currently mass-reared using a cowpea and maize flour-based meridic diet. In this study, the suitability of germinating seeds from three cowpea varieties, Kpodji-guegue, Tawa and TVX3236, as substrates, was tested for rearing A. taragamae under laboratory conditions. The seeds that were soaked for 48 h were the most suitable for M. vitrata larval rearing with up to 87 % survival. The highest parasitism rate of M. vitrata larvae by A. taragamae was observed on the local variety Tawa. Compared to meridic diet, the development cycle of the parasitoid was shorter on Tawa sprouts which also lead to the highest lifetime fecundity. The parasitoid sex ratio varied significantly between feeding substrates with a higher proportion of female wasps on the improved varieties TVX2336 and local variety Kpodji-guegue. Rearing M. vitrata larvae on germinating cowpea grains is 4.38 times cheaper than on meridic diet. The data are discussed with emphasis on the effects of feeding substrates quality on life history parameters of insect pests and their parasitoids.

Aphis gossypii Glover (Hemiptera: Aphididae) is one of the major pests of okra. Damage severity and high levels of infestation have led to widespread use of chemical insecticides. Okra is ranked fourth in Cameroon among vegetable crops on which chemical insecticides are applied. The objectives of this study were to evaluate resistant okra accessions identified in previous studies, to identify their categories of resistance, and to assess their effects on the non-preference, development, and reproduction of A. gossypii . Results showed that VI041210 was resistant to aphid infestation during the first season, and VI057245 and Gombo cafeier were resistant during the second season. Kirikou and VI060794 had the highest yields during the first season, although Kirikou was moderately susceptible to aphid infestation. VI041210 was susceptible to aphid infestation during the second season but produced the highest yield. These results indicate that tolerance occurred in some of the accessions. Aphids did not discriminate between resistant and susceptible accessions, indicating that antixenosis (non-preference) was not a category of resistance found in these accessions. VI041210, VI057245, and Gombo cafeier were the most resistant due to lower infestation levels, probably due to their antibiotic properties. Considering constitutive resistance, aphid development was poor, with the longest molting and generation time (To = 15.9) on VI057245 at the vegetative plant growth stage, leading to poor reproduction (lowest intrinsic and finite rates of natural increases: 0.25 and 1.3 aphids, respectively). Considering induced resistance, observed only in VI041210, nymphal development time was longest (14.2 d) leading to one of the lowest net reproductive rates at the vegetative and reproductive plant growth stages, 27.1 and 27.8, respectively. Thus, tolerance and antibiosis were categories of resistance found in these accessions, but antixenosis was not documented. Resumen Aphis gossypii Glover (Hemiptera: Aphididae) es una de las principales plagas de okra. La severidad de los danos y los altos niveles de infestacion han llevado al uso generalizado de insecticidas quimicos. La okra ocupa el cuarto lugar en Camerun entre los cultivos de hortalizas en los que se aplican insecticidas quimicos. Los objetivos de este estudio fueron evaluar las muestras resistentes de okra identificadas en estudios anteriores, identificar sus categorias de resistencia y evaluar sus efectos sobre la no preferencia, el desarrollo y la reproduccion de A. gossypii . Los resultados mostraron que VI041210 fue resistente a la infestacion de afidos durante la primera temporada y VI057245 y Gombo cafeier fueron resistentes durante la segunda temporada. Kirikou y VI060794 tuvieron los rendimientos mas altos durante la primera temporada, aunque Kirikou fue moderadamente susceptible a la infestacion de afidos. VI041210 fue susceptible a la infestacion de afidos durante la segunda temporada, pero produjo el rendimiento mas alto. Estos resultados indican que se produjo tolerancia en algunas de las muestras. Los afidos no discriminaron entre v muestras resistentes y susceptibles, lo que indica que la antixenosis (no preferencia) no era una categoria de resistencia encontrada en estas muestras. VI041210, VI057245 y Gombo cafeier fueron los mas resistentes debido a niveles de infestacion mas bajos, probablemente debido a sus propiedades antibioticas. Considerando la resistencia constitutiva, el desarrollo de afidos fue pobre, con el tiempo de muda y generacion mas largo (To = 15.9) en VI057245 durante la etapa de crecimiento vegetativo de la planta, lo que resulto en una reproduccion baja (tasas intrinsecas y finitas naturales mas bajas: 0.25 y 1.3 afidos respectivamente). Considerando la resistencia inducida, observada solo en VI041210, el tiempo de desarrollo de la ninfa fue mayor (14.2 dias) y resulto en una de las tasas reproductivas netas mas bajas en las etapas de crecimiento vegetativo y reproductivo de la plantas, 27.1 y 27.8, respectivamente. Por lo tanto, la tolerancia y la antibiosis fueron categorias de resistencia encontradas en estas muestras, pero la antixenosis no fue documentada. View this article in BioOne

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), a devastating pest of tomato, invaded Tanzania in 2014. There is now a pressing need to determine the extent of T. absoluta infestations in tomato, other solanaceous crops, and wild plants of Tanzania, to support research and to develop pest management programs. In Sep and Oct 2015, we visited 15 randomly selected villages in 4 leading tomato-producing districts (Arumeru, Lushoto, Kilolo, and Mvomero) and sampled fields representing 9 solanaceous crops and weeds. Tuta absoluta was present in all 4 districts. Overall, in tomato ( Solanum lycopersicum L.) T. absoluta established 1.0 ± 1.3 (mean ± standard deviation) mines per leaf and damaged 15 ± 15% of fruits; in eggplant (aubergine) ( Solanum melongena L.) it established 0.3 ± 0.7 mines per leaf and damaged 0 ± 0% of fruits; in potato ( Solanum tuberosum L.) T. absoluta established 0.17 ± 0.1 mines per leaf; and in 2 African nightshades ( Solanum nigrum L. and Solanum americanum Mill.) T. absoluta established 0.02 ± 0.03 mines per leaf (fruits of the latter 2 were not sampled). Pepper ( Capsicum annuum L.) and African eggplant ( Solanum aethiopicum L.) were not affected by T. absoluta . We found 3 solanaceous weeds in the vicinity of T. absoluta -infested fields in Arumeru District: Solanum incanum L. , Datura stramonium L. , and Nicandara physalodes (L.) Gaertn. None of these species were infested by T. absoluta ; however, the latter 2 were infested by Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), which has habits and larvae that resemble those of T. absoluta . Resumen El minador del tomate, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), una plaga devastadora de tomate, invadio Tanzania en el 2014. Actualmente existe una necesidad apremiante de determinar la extension de la infestacion de T. absoluta en tomate y otros cultivos de solanaceas y plantas silvestres de Tanzania para apoyar la investigacion y el desarrollo de programas de manejo de plagas. En sep y oct del 2015, visitamos 15 aldeas seleccionadas al azar en 4 distritos productores de tomate (Arumeru, Lushoto, Kilolo, y Mvomero) y muestreamos campos que representan 9 cultivos de solanaceas y malezas. Tuta absoluta estuvo presente en los 4 distritos. En general, en tomate ( Solanum lycopersicum L.), T. absoluta establecio 1.0 ± 1.3 (media ± desviacion estandar) minas por hoja y dano 15 ± 15% de las frutas; en berenjena ( Solanum melongena L.) establecio 0.3 ± 0.7 minas por hoja y dano 0 ± 0% de las frutas; en papa ( Solanum tuberosum L.) establecio 0.17 ± 0.1 minas por hoja; y en 2 especies de tomatillo de diablo africano ( Solanum nigrum L. y Solanum americanum Mill.) establecio 0.02 ± 0.03 minas por hoja (no se tomaron muestras de los frutos de los ultimos 2). El chile dulce ( Capsicum annuum L.) y la berenjena africana ( Solanum aethiopicum L.) no se vieron afectadas por T. absoluta . Encontramos 3 malezas solanaceas cerca de los campos infestados de T. absoluta en el distrito de Arumeru: Solanum incanum L., Datura stramonium L. y Nicandara physalodes (L.) Scop. Ninguna de estas especies fue infestada por T. absoluta ; sin embargo, estos ultimos 2 fueron infestados por Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), que tiene habitos y larvas que se asemejan a T. absoluta . View this article in BioOne

It has been a challenge to establish the accurate diagnosis of developmental tooth anomalies based on periapical radiographs. Recently, three-dimensional imaging by cone beam computed tomography has provided useful information to investigate the complex anatomy of and establish the proper management for tooth anomalies. The most severe variant of dens invaginatus, known as dilated odontome, is a rare occurrence, and the cone beam computed tomographic findings of this anomaly have never been reported for an erupted permanent maxillary central incisor. The occurrence of talon cusp occurring along with dens invaginatus is also unusual. The aim of this report was to show the importance of cone beam computed tomography in contributing to the accurate diagnosis and evaluation of the complex anatomy of this rare anomaly.

Oogenesis and oviposition dynamics of female moths of tomato fruitworm, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), were compared in a monoculture of tomato (Solanum lycopersicum L.) and in mixtures with a highly preferred but unsuitable host plant, Solanum viarum Dunal. Female H. armigera provided with S. viarum laid many more eggs than those provided with tomato, both in choice and no-choice experiments. Gravid female moths did not display any preference for oviposition neither between young or old plants of S. viarum or tomato, nor between young and old leaves of S. viarum. Larval mortality and larval developmental period significantly increased, with subsequent reduction in pupal weight, when H. armigera larvae fed on S. viarum leaves compared to a meridic diet. Oviposition of female moths significantly increased in tomato in the presence of S. viarum volatiles. However, in screen cages with an increasing percentage of S. viarum as a trap crop, the number of eggs laid on tomato as the main crop was the same. The results of this study are discussed in light of the possibility of using S. viarum as a ‘dead-end’ trap crop.

The larvae of the legume pod borer, Maruca vitrata (Lepidoptera: Pyralidae), cause severe damage on economically important legume crops in the tropics. The female moth produces volatile components to attract males for mating. The so-called sex pheromones are species-specific multi-component blends and are used as lures in crop protection for pest monitoring. Their chemical identification and ratios is critical to design efficient lures. The following sex pheromone components for M. vitrata have been described: (E, E)-10,12-hexadecadienal (major compound), (E, E)-10,12-hexadecadienol and (E)-10-hexadecenal (minor components). The ratio of 100:5:5 of these components was the most attractive in trapping experiments in Benin, Africa. According to this ratio, a synthetic pheromone lure was developed for commercial use. But the commercially available blend was not attractive in field trapping experiments in other regions of sub-Saharan Africa and Southeast Asia. These findings lead to the conclusion that there is a possible polymorphism in the blend composition of the M. vitrata sex pheromone among populations from different geographical regions. In Taiwan, M. vitrata moths were never caught efficiently by the commercially available pheromone lures and traps. This paper reports trap and lure optimization experiments for effective trapping of Taiwanese M. vitrata moths in different leguminous crops.

Plant diseases caused by vector-transmitted viruses like begomovirus inflict serious damage in terms of yield and colossal loss in many crops, predominantly Chilli. Coupled with bleak farm awareness and lack of management options, they could severely hamper remuneration prospects. In this connection, the profitability of the farm level begomovirus management strategies has been analyzed in this study. A sample of 100 chilli farmers were surveyed with focus on their perceptions of begomovirus caused diseases. Findings revealed a majority of farmers (80 per cent) experienced cross loss due to viral diseases. Positive changes in output and production cost were also reported with the adoption of management strategies, which in turn were categorized in to: low, medium and high. Besides, it was also revealed that when compared with no management strategy, the change in the gross margin was 17 per cent, 26 per cent and 80 per cent after the adoption of low, medium and high level of management strategies, respectively.

Dens Invaginatus is a dental malformation that poses diagnostic difficulties in the clinical context. This anomaly may increase the risk of pulp disease and can potentially complicate endodontic procedure due to the aberrant root canal anatomy. Compared to conventional radiographs, three-dimensional images obtained with Cone Beam Computed Tomography (CBCT) are invaluable in the diagnosis of the extent of this anomaly and in the appropriate treatment planning. Oehler’s classification (1957) for Dens Invaginatus (DI) into three types depending on the depth of the invagination has been used for treatment planning. Of the three types Type III DI is characterized by infolding of the enamel into the tooth up to the root apex and is considered as the most severe variant of DI and hence the most challenging to treat endodontically, due to the morphological complexities. This report describes a case of Oehler’s Type III DI in a necrotic permanent maxillary lateral incisor in which CBCT images played a key role in diagnosis and treatment planning. The case was managed successfully by a combination of nonsurgical and surgical endodontic therapy with orthograde and retrograde thermoplastic gutta percha obturation.

The parasitoid, Diadegma semiclausum (Hymenoptera: Ichneumonidae) is one of the most effective parasitoids of diamondback moth (DBM) in the highlands (> 1600 m above sea level) of Asia. A Diadegma population from the lowland areas of Homs, Syria (about 203–487 m above sea level) was examined to determine if it differs at the species-level from the D . semiclausum and other Diadegma populations present in different countries using molecular diagnostic tools. Phylogenetic analysis based on the neighbor-joining method using the mitochondrial cytochrome oxidase I (COI) and the nuclear internal transcribed spacer 2 (ITS2) sequences grouped the Homs (Syria) Diadegma population with D. semiclausum populations from other countries. The results suggest that D. semiclausum occurs in the lowland conditions in Homs (Syria), where the temperature is higher. The Homs (Syria) strain did not show any variations in the parasitism when the parasitized host (DBM) larvae were exposed to varying temperatures for 24 h. It could not survive when the parasitized DBM larvae were continuously reared at 35 °C; however it inflicted significantly higher parasitism when the parasitized DBM larvae were reared at day and night temperatures of 35 °C and 20 °C, respectively. Preliminary results indicate that the D. semiclausum strain from Homs (Syria) possesses some level of heat tolerance, which could be exploited for successful management of DBM in the tropical lowlands.

Chigurupati Ramachandraiah and Ramasamy Srinivasan argue that special economic zones in India are not pro-poor people centred development but rather are a form of land grab that dispossess rural peasants to the benefit of big capital and the elite. After 60 years of independence, India is experiencing ‘social justice in reverse gear’ with a failure to uphold the land rights to the poor.

The chrysomelid beetle Phyllotreta striolata is an important pest of Brassicaceae in Southeast Asia and North America. Here, we identified the aggregation pheromone of a population of P. striolata from Taiwan, and host plant volatiles that interact with the pheromone. Volatiles emitted by feeding male P. striolata attracted males and females in the field. Headspace volatile analyses revealed that six sesquiterpenes were emitted specifically by feeding males. Only one of these, however, elicited an electrophysiological response from antennae of both sexes. A number of host plant volatiles, e.g., 1-hexanol, (Z)-3-hexen-1-ol, and the glucosinolate hydrolysis products allyl isothiocyanate (AITC), 3-butenyl isothiocyanate, and 4-pentenyl isothiocyanate also elicited clear responses from the antenna. The active male-specific compound was identified as (+)-(6R,7S)-himachala-9,11-diene by chiral stationary phase gas-chromatography with coupled mass spectrometry, and by comparison with reference samples from Abies nordmanniana, which is known to produce the corresponding enantiomer. The pheromone compound was synthesized starting from (-)-α-himachalene isolated from Cedrus atlantica. Under field conditions, the activity of the synthetic pheromone required concomitant presence of the host plant volatile allyl isothiocyanate. However, both synthetic (+)-(6R,7S)-himachala-9,11-diene alone and in combination with AITC were attractive in a two-choice laboratory assay devoid of other natural olfactory stimuli. We hypothesize that P. striolata adults respond to the pheromone only if specific host volatiles are present. In the same laboratory set up, more beetles were attracted by feeding males than by the synthetic stimuli. Thus, further research will be necessary to reveal the components of a more complex blend of host or male-produced semiochemicals that might enhance trap attractiveness in the field.

The diamondback moth (DBM), Plutella xylostella (L.), remains a major pest of brassica crops worldwide. DBM has been estimated globally to cost US$ 1 billion in direct losses and control costs. Chemical control of this pest remains difficult due to the rapid development of resistance to insecticides and to their effect on natural enemies. These problems are especially severe in South Asia and Africa where lack of knowledge, limited access to newer and safer insecticides, and a favourable climate result in DBM remaining a serious year-round pest which substantially increases the cost and uncertainty of crop production. Despite these problems, application of synthetic insecticides remains overwhelmingly the most common control strategy. Biologically-based efforts to control DBM in Africa and Asia have focused strongly on parasitoid introductions. However, despite the identification and deployment of promising parasitoids in many regions, these efforts have had limited impact, often because farmers continue early-season spraying of broad-spectrum insecticides that are lethal to parasitoids and thus exacerbate DBM outbreaks. A significant driver for this pattern of insecticide use is the presence of aphids and other pests whose appearance initiates inappropriate spraying. Despite often extensive training of producers in farmer field schools, many growers seem loath to discard calendar or prophylactic spraying of insecticides. The introduction of an IPM technology that could replace the use of broad-spectrum insecticides for DBM and other key Lepidoptera is crucial if the benefits of parasitoid introduction are to be fully realised. The deployment of DBM-resistant brassicas expressing proteins from Bacillus thuringiensis could help to break this cycle of insecticide misuse and crop loss, but their deployment should be part of an integrated pest management (IPM) package, which recognises the constraints of farmers while addressing the requirement to control other Lepidoptera, aphids and other secondary pests.

Advances in transgenic plants expressing Bacillus thuringiensis (Bt) insecticidal gene(s) offer a promising alternative to traditional insecticides for control of lepidopteran pests on important cruciferous vegetable crops such as cabbage and cauliflower. A public-private partnership, the Collaboration on Insect Management for Brassicas in Asia and Africa (CIMBAA), was formed in 2005 with the goal of developing dual-gene Bt cauliflower and cabbage, initially for India, to replace the use of broad spectrum, traditional insecticides. As a first step in this effort, the major lepidopteran pests of cruciferous vegetable crops [Plutella xylostella (L.), Pieris rapae (L.), Pieris brassicae (L.), Crocidolomia binotalis (L.), Hellula undalis (F.), Diacrisia obliqua Walker, Spodoptera litura F., and Helicoverpa armigera (Hubner)] were collected over a large geographic area (India, Indonesia, Taiwan, China, Australia, and the United States) and tested against purified Cry1Ba2 and Cry1Ca4 toxins, the toxins proposed to be expressed in the CIMBAA plants. Our results demonstrate that Cry1Ba2 and Cry1Ca4 were effective against the primary target of the CIMBAA plants, P. xylostella, regardless of geographic location, and had LC50 values

Cabbage (Brassica olearaceae var. capitata) and cauliflower (Brassica oleracea var. botrytis) are two major vegetables produced and consumed in India. Over the years, they have been cultivated more intensively. This has resulted in higher rates of pest infestation, especially by the diamondback moth (Plutella xylostella) and higher pesticide use. This, in turn, has contributed to insecticide resistance, environmental degradation, and human health impacts, which have triggered a growing interest in alternative management techniques. There is a dearth of knowledge on current pest management practices in cabbage and crucifer. Knowledge about pest management practices is necessary to develop appropriate strategies such as Integrated Pest Management. The main purpose of this study was to obtain comprehensive information on pest management practices among farmers growing cabbage and cauliflower in India. A survey was conducted in the states of Gujarat, West Bengal, and Karnataka from October 2006 through January 2007. Three hundred farmers were interviewed to obtain information on pesticide use in cabbage and cauliflower production, the cost of pesticide use, and socioeconomic characters that influence cabbage and cauliflower production. Farmers relied on pesticides as the major and often exclusive crop protection strategy. Ten of the active ingredients (16.4% of all pesticides reported by all farmers in this survey) were listed as extremely or highly hazardous (classes Ia and Ib) by the World Health Organization. The results confirmed that pesticide use differs between states of India, but that location alone does not determine pesticide spraying pattern. A regression model was used to identify determinants of pesticide application frequency and pesticide cost per hectare. After controlling for location, individual level variables, such as age, education and experience, had significant effects on how often farmers sprayed. Farmers also spent more for pesticides, and sprayed more frequently on cauliflower than on cabbage and on open-pollinated varieties than on hybrid varieties. Our findings highlight the excessive use of pesticides in cabbage and cauliflower, and the reliance on pesticides as the only pest management strategy. The results confirm the need for alternative management strategies. Bt vegetables may be one of these alternative strategies. However, it is questionable whether cultivation of Bt vegetables will reduce the strong reliance on pesticides. Small-scale farmers will need training in the identification of pests, natural enemies, basic ecology, and integrated pest management strategies to ensure sustainable and safe vegetable production.

A nucleopolyhedrovirus (MaviMNPV) was isolated from diseased larvae of legume pod borer (LPB), Maruca vitrata, at Tainan in Taiwan. Electron microscopical studies on the ultrastructure of MaviMNPV occlusion bodies (OBs) showed several virions (up to 19) with multiple nucleocapsids (up to 6) packaged within a single viral envelope. The diameter of OBs was 0.9 to 1.3 µm with a mean of 1.152±0.116 µm. The complete sequence of the MaviMNPV polyhedrin (Polh) gene contained 735 nucleotides (GenBank accession number DQ399596). Phylogenetic analyses using the complete sequence of the Polh gene of MaviMNPV indicated that this virus clusters with Group I NPVs. The genome size of MaviMNPV estimated with restriction enzymes viz., HindIII, EcoRI, BglII and PstI was 113.41 ± 1.50 kbp. First instar LPB larvae were the most susceptible stage (LC50 2.053 × 102 OBs/ml) followed by second, third and fourth instars with the median lethal concentrations (LC50s) 1.410 × 103, 2.390 × 103 and 2.636 × 103 OBs/ml, respectively. This is the first record of this virus from this region.

The legume pod borer, Maruca vitrata, is a pantropical pest on leguminous crops. (E,E)-10,12-Hexadecadienal, (E,E)-10,12-hexadecadienol, and (E)-10-hexadecenal were described previously as sex pheromone components for this nocturnal moth. A blend of these components in a ratio of 100:5:5 attracted males in field trapping experiments in Benin, but not in Taiwan, Thailand, or Vietnam. This finding suggests geographic variation in the pheromone blend between Asian and West African populations of M. vitrata. We, therefore, determined the pheromone compositions of single pheromone glands of females from the three Asian regions and from Benin by gas chromatography—mass spectrometry. Additionally, we compared the responses of males from Taiwan and Benin to calling females and to gland extracts of females from both regions in laboratory no-choice and two-choice assays. Chemical analysis revealed the presence of (E,E)-10,12-hexadecadienal and (E,E)-10,12-hexadecadienol, as well as the absence of (E)-10-hexadecenal in all four populations. The relative amounts of the detected compounds did not vary significantly among the insect populations. The behavioral bioassays showed that Taiwanese and Beninese males were similarly attracted to females from both regions, as well as to their gland extracts. As a result, we did not find geographic variation in the sexual communication system of M. vitrata between West African and Asian insect populations.

Previous studies on the legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae), a serious pest of cowpea, Vigna unguiculata (L.) Walp. (Fabales: Fabaceae), in sub-Saharan Africa have focused on sex pheromones, but the role of the host plant on sexual behavior has not been explored. We investigated this interaction in the laboratory using behavioral assays and chemical analyses. We found that the presence of cowpea seedlings and a dichloromethane extract of the leaf increased coupling in the legume pod borer by 33 and 61 %, respectively, compared to the control, suggesting the involvement of both contact and olfactory cues. We used coupled gas chromatography-electroantennographic detection (GC/EAD) and GC-mass spectrometry (GC/MS) to identify compounds from the cowpea leaf extract, detected by M. vitrata antenna. We found that the antennae of the insect consistently detected four components, with 1-octen-3-ol identified as a common and dominant component in both the volatiles released by the intact cowpea plant and leaf extract. We therefore investigated its role in the coupling of M. vitrata. In dose-response assays, 1-octen-3-ol increased coupling in M. vitrata with increasing dose of the compound compared to the control. Our results suggest that the cowpea volatile 1-octen-3-ol contributes to M. vitrata sexual behavior.

Background Culex quinquefasciatus, an arboviral and filarial vector, is present year round in several cities of the Republic of Benin. There is more information on the resistance status to malaria vectors compared to Culicines. It is therefore unfortunate that the international focus is on Anopheles control and not so much done against Cx. quinquefasciatus, a rather more resilient mosquito to many insecticides that deserves attention. The present study aims to assess the resistance status of Cx. quinquefasciatus to carbamates, pyrethroids and organochlorine and discuss the implications for vector control in four contrasting localities of the country. Methods Four contrasting localities of the country were selected for mosquito collection during the dry season based on their variation in agricultural production, use of insecticides and/or ecological settings. Bioassay were performed on adults collected from the field to assess the susceptibility of Cx. quinquefasciatus to insecticide-impregnated papers (permethrin 0.75%, delthamethrin 0.05%, DDT 4%, and bendiocarb 0.1%) following WHOPES guidelines. Molecular assays were carried out to detect the presence of knock down resistance (kdr) and acetylcholinesterase (ace. 1) mutations in surviving specimens using PCR techniques. Results WHO diagnostic tests showed high frequency of resistance in Cx. quinquefasciatus to permethrin (ranging from 4 to 24% mortality), deltamethrin (24 to 48%), DDT (4 to 12%) and bendiocarb (60 to 76%) in the four selected areas. This was consistent with the presence of target site insensitivity due to kdr and ace.1 mutations, which were significantly higher in areas where farmers used insecticides for pests control than in areas where no insecticides were used (p < 0.05.). Conclusion These findings showed that wild populations of Cx. quinquefasciatus have developed resistance against pyrethroids, organochlorine and carbamate. This situation of resistance may seriously jeopardize the efficacy of Insecticide Residual Spray (IRS) and Long-Lasting Insecticide nets (LLINs) on which, most African countries including Benin, rely to reduce malaria transmission.

Insect pheromones can be used to monitor, mass-trap, and/or disrupt the mating process of insect pests. Sex pheromones of major lepidopteran pests such as tomato fruit worm (Helicoverpa armigera) and common armyworm (Spodoptera litura) are widely used as monitoring lures in tropical vegetable production systems. The use of sex pheromone traps as a mass-trapping tool against polyphagous insects is limited. However, such traps are highly effective in reducing the damage and yield losses caused by monophagous insects such as eggplant fruit and shoot borer (Leucinodes orbonalis), as demonstrated in the Indo-Gangetic Plains of South Asia by AVRDC—The World Vegetable Center. By definition, pheromones are species-specific, yet “cross-talks” were observed when we attempted to refine sex pheromones for monitoring and mass-trapping legume pod borer (Maruca vitrata) and cucumber moth (Diaphania indica). In addition to sex pheromones, the possible use of aggregation pheromone as a pest management tool has been attempted in striped flea beetle (Phyllotreta striolata) on vegetable brassicas. Recent research indicated that pheromones act synergistically when combined with host plant volatiles, a process validated against P. striolata at AVRDC.

The tomato fruitborer, Helicoverpa armigera Hub., and the whitefly, Bemisia tabaci Genn., can not be easily controlled in tomato, Lycopersicon esculentum Mill. The insects are capable of rapidly evolving resistance to insecticides. Exploiting resistance mechanisms is a sustainable strategy to combat these pests. Resistance to these pests was identified in tomato accessions by evaluating resistance mechanisms. Among the accessions screened for whitefly resistance, ‘LE 598’ had more trichomes (72/mm2) on both leaf surfaces. Similarly, ‘LE 104’ had 53.0/mm2, and is resistant to fruitborer. Whiteflies preferred to lay more eggs on the abaxial (4.0 to 31.5/leaf) than on the adaxial leaf surface (1.0 to 24.5/leaf). Accession ‘COTLCVRH 1’ had the lowest number of eggs on the abaxial surface (4.0 eggs/leaf) and 1.0 egg/leaf on the adaxial surface. There was a linear relationship between trichome density and oviposition preference by whitefly (r = 0.91). Trichomes were most dense on ‘LE 104’ and it was pr...

The tomato fruitborer (TFB), Helicoverpa armigera Hub., is one of the most difficult pests to control with insecticides. Development of cultivars that are resistant to this insect has become an important strategy in management. Resistant/tolerant accessions of tomato (Lycopersicon esculentum Mill.) to TFB have been identified based on feeding and ovipositional behavior of TFB. The moths laid more eggs on accessions LE 4 (52 eggs/plant), LE 104 (73) and LE 281 (57) than on LE 355 (11). Biochemical assays indicated that the acylsugar contents in leaves of tomato accessions varied from 38 to 266 nmol/cm2. High acylsugar content was negatively associated with number of eggs laid/ plant (r = -0.94). Content of alpha-tomatine in fruit varied from 0.57 to 3.51 mg.g−1 of fresh tissue. The alpha-tomatine concentration was weakly, and negatively, associated with percent fruit damage by TFB (r = -0.39). The fruit pigments lycopene and carotene influenced the feeding of TFB as there were differences in feedi...