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Papaya mealybug Paracoccus marginatus (Williams and Granara de Willink) is an economical pest of mulberry causing significant crop loss by damaging the leaves. This study was undertaken to investigate the internal structure of papaya mealybug, that was morphologically examined through a stereo-zoom microscope which includes digestive system, respiratory system, nervous system, excretory system, pseudovitellus and muscular system. The internal anatomy of papaya mealybug revealed that the digestive system is associated with fore-gut (pharynx and oesophagus), mid-gut (stomach /dilated sac), filter chamber and hind-gut (ileum and rectum). The filter chamber is enclosed with posterior extremity of oesophagus, anterior mid-gut, posterior mid-gut, anterior extremity of ileum and rectum. Either side of the oesophageal tube has a pair of fully formed salivary gland. Two malpighian tubules approximate of its body length were seen adjacent to the hind-gut. Nervous system is mainly composed of supra-oesophageal ganglion (brain) with a small lobe called sympathetic ganglion, sub-oesophageal ganglion and thoracico-abdomial ganglion. Tracheal trunks emerge from four spiracles, which were encircled by wax glands at its base. Reproductive system consists of three globular genital glands with a single translucent globular spermatheca, a pair of ovaries arranged in Y shaped structure with numerous ovarioles. The ventral longitudinal muscles protrude from diamond shaped thoracic furca and dorsal longitudinal muscles present beneath the dorsal region extends throughout the body. An oval shaped pseudo-vitellus composed of bacterio-cysts is present in the centre of the ventral region. The purpose of this study is to highlight some of the important internal anatomical features of adult female papaya mealybug Paracoccus marginatus (Williams and Granara de Willink). [ABSTRACT FROM AUTHOR]

Abstract Background The North Eastern Region (NER) of India is well known for its rich biodiversity and organic cultivation; however, this is one of the least investigated regions owing to its remoteness. A field study on papaya mealybug (PMB) was conducted to know its present status in Dibrugarh district of Assam, NER India, after its first entry in 2012. Results The pest was initially confined in urban and peri-urban localities in 2012 and has now made its entry even in remote villages too; however, many villages still remain uninfested. PMB has not damaged crops much the way it did in major papaya producing states of India. Out of 217 farmers surveyed, only 31.8% have experienced the infestation of PMB in their crops. The pest has now been recorded in places within an elevation of 98–129 m above MSL. The village homesteads help the pest establish in the ecosystem through natural host shifting. 89.9% farmers adopted either no management practices or applied non-chemical measures. We found the presence of more number of Spalgis immatures in the colonies of PMBs in hibiscus than in papaya. After the first invasion of PMB in Assam, initially it was also worried that the pest might invade tea crop and affect the tea economy of the state; however, no report on PMB infestation on tea crop has been found so far. Conclusions The PMB has acclimatized and established itself in the crop ecosystem of Assam by natural host shifting. The trend of infestation is constant or increasing. No programme on classical biological control of PMB was taken in the farmers’ fields of the state, but there is no hue and cry situation on the crop damage by PMB. High rainfall affected the spread of the pest and predation by Spalgis sp might have resulted in reduction in population. We recorded variable abundance of S. epeus larva in PMB colonies in different host plants based on which we can formulate the bio-control module for PMB. The detailed study on the role of rainfall and natural enemies on population dynamics of PMB is a researchable issue.

Background: The North Eastern Region (NER) of India is well known for its rich biodiversity and organic cultivation; however, this is one of the least investigated regions owing to its remoteness. A field study on papaya mealybug (PMB) was conducted to know its present status in Dibrugarh district of Assam, NER India, after its first entry in 2012. Results: The pest was initially confined in urban and peri-urban localities in 2012 and has now made its entry even in remote villages too; however, many villages still remain uninfested. PMB has not damaged crops much the way it did in major papaya producing states of India. Out of 217 farmers surveyed, only 31.8% have experienced the infestation of PMB in their crops. The pest has now been recorded in places within an elevation of 98–129 m above MSL. The village homesteads help the pest establish in the ecosystem through natural host shifting. 89.9% farmers adopted either no management practices or applied non-chemical measures. We found the presence of more number of Spalgis immatures in the colonies of PMBs in hibiscus than in papaya. After the first invasion of PMB in Assam, initially it was also worried that the pest might invade tea crop and affect the tea economy of the state; however, no report on PMB infestation on tea crop has been found so far. Conclusions: The PMB has acclimatized and established itself in the crop ecosystem of Assam by natural host shifting. The trend of infestation is constant or increasing. No programme on classical biological control of PMB was taken in the farmers' fields of the state, but there is no hue and cry situation on the crop damage by PMB. High rainfall affected the spread of the pest and predation by Spalgis sp might have resulted in reduction in population. We recorded variable abundance of S. epeus larva in PMB colonies in different host plants based on which we can formulate the bio-control module for PMB. The detailed study on the role of rainfall and natural enemies on population dynamics of PMB is a researchable issue. [ABSTRACT FROM AUTHOR]

The life table data of papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), on the jatropha, Jatropha integerrima (Euphorbiaceae), were collected using individually- and group-rearing and analyzed by using the age-stage, two-sex life table. Because the male individuals have six stages while the female individuals have only five stages, a new method was developed for a correct description of life stages and life table analysis. In general, the developmental durations of individually-reared insects were significantly longer than those of group-reared insects. Although the mean fecundity (F = 167.84 eggs/female) and the net reproductive rate (R0 = 62.10 offspring) of the individually-reared cohort were significantly higher than those of group-reared cohort (F = 66.5 eggs/female and R0 = 18.62 offspring), there were no significant differences in the population growth rates, i.e., intrinsic rate of increase r and finite rate of increase λ. Because the age variable x is an exponent in the Euler-Lotka equation, the first reproductive age and total preoviposition period are important factors in the determining the value of population growth rates. The life table data were used to simulate the population growth and timing of the control. Our results demonstrated that for grouplived insects like papaya mealybug, life table data collected using group-reared cohort is a better option for simulating pest population growth and management than data from individually-reared cohort. [ABSTRACT FROM AUTHOR]

Purpose: Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) is a well-known biocontrol agent that is widely used to control soft-bodied insects including papaya mealybug. This study aimed to evaluate the behaviour of C. montrouzieri to chemical simulants associated with honeydew (HD) and crushed papaya mealybugs (CPMBs), under laboratory conditions. Research Method: The larvae and adult stages of C. montrouzieri were introduced into a Petri dish containing HD or CPMBs treated and untreated Carica papaya (Papaya) leaf discs, and the behaviour was recorded for 20 minutes using video surveillance. Searching time, walking speed, and number of turns on leaf discs were quantified. Findings: Results revealed that the searching time of C. montrouzieri, on papaya leaf discs was significantly varied with different larval instars and adults (F (4,298) = 17.21, p<0.05) as well as leaf-coated substances (F (2,298) = 78.07, p<0.05). When considering all larval instars of C. montrouzieri searching time on CPMBs (690.7 ± 25.3 s) was significantly higher compared to HD (524.8 ± 33.5 s) and clean leaf disc (219.6 ± 34.4 s) (F (2, 227) = 60.61, p<0.05). The searching period of the first larva (L1) was significantly higher compared to adults in all treatments (p<0.05). The walking speed of the fourth larva (L4) and adults of C. montrouzieri on HD and CPMBs leaf discs was significantly lower compared to that of clean leaf discs. The number of turns per unit path length was significantly higher in both HD (1.100/cm) and CPMBs (1.129 / cm) leaf discs compared to the control (0.501/cm) concerning larvae and adults. Originality/value: It leads to the conclusion that HD and CPMBs considerably change the searching behaviour of larvae and adults of C. montrouzieri. Further work should be focused on examining and utilizing these chemical cues for searching to enhance the efficacy of C. montrouzieri in controlling papaya mealybug. [ABSTRACT FROM AUTHOR]

Budidaya alpukat mentega (Persea americana) yang ada di Desa Ternadi belum sepenuhnya menggunakan teknik yang tepat, terutama saat pengendalian hama penyakit. Pengendalian hama yang dilakukan menggunakan pestisida kimia dan tidak dilakukan pengendalian secara terpadu. Hama yang sering menyerang tanaman alpukat adalah kutu yang berwarna putih (Paracoccus marginatus) atau dikenal juga sebagai kutu kebul. Ekskresi kutu putih menyebabkan daun menjadi berwarna hitam dan menutupi seluruh daun. Metode kegiatan adalah survei, penyuluhan, praktik, dan pendampingan. Kegiatan pengabdian dilakukan di balai Desa Ternadi tanggal 12 Desember 2022 sampai dengan 3 Januari 2023, yang dihadiri kurang lebih 30 petani alpukat Desa Ternadi. Didapatkan hasil bahwa kutu putih menjadi permasalahan utama di budi daya alpukat, sehingga dilakukan penyuluhan yang juga di lengkapi praktik pengendalian hama tersebut. Antusias dari peserta baik hal ini juga dilihat dari banyaknya peserta serta penerapan pengendalian sesuai arahan Ketika penyuluhan yang tetap diterapkan oleh masyarakat Ketika kegiatan pendampingan oleh tim.

The cotton mealybug, Phenacoccus solenopsis Tinsley and papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) are becoming major threats to the production of Gymnema sylvestre R. Br. (Asclepiadaceae) in India. Management mainly depends on chemical insecticides which cause a serious problem of pesticide residue and insecticide resistance. The use of biorational insecticides such as biopesticides, botanicals, insect growth regulators, and microbial insecticides is important components of an Integrated Pest Management (IPM) program for successful management. We evaluated the bio-efficacy of twelve biorational insecticides, including entomopathogenic fungi (EPF), using the leaf spray method in laboratory conditions at 25 ± 1 °C, 70 % ± 5 % RH. The results revealed that the highest percent mortality was recorded by acetamiprid 20 % SP (100.00 %), followed by azadirachtin (98.27 %), Lecanicillium muscarium (2 × 109 spores/mL) (85.70 %) and Ocimum sanctum leaf extract (76.87 %) at 120 h after treatment (HAT) in P. solenopsis. In P. marginatus, 100.00 %, 96.39 % and 85.67 % and 74.90 % mortalities were achieved by acetamiprid 20 % SP, azadirachtin, L. muscarium (2 × 109 spores/mL) and O. sanctum leaf extract, respectively, at 120 HAT during the first spray. Various biorational insecticides showed a more or less similar trend of percent mortality in both species during the second spray. In both species, the lowest percent mortality was recorded by Andrographis paniculata leaf extract (46.29, 44.54) and (41.03, 46.39) at 120 Hours after treatment in the first and second spray, respectively. It was concluded that all the prescribed treatments are more effective than the control. Overall, azadirachtin recorded the highest percent mortality after acetamiprid and had the shortest LT50 (12.52 h) and (13.87 h) values in P. solenopsis and P. marginatus, respectively. Our study emphasizes that biopesticides like Azadirachtin 1 % EC (10000 ppm), L. muscarium (2 × 109 spores/mL) (5 mL/L) and O. sanctum leaf extract (5 %) may be recommended as alternatives to synthetic insecticides. Botanicals and EPF would be the most effective approach for sustainable integrated management of P. solenopsis and P. marginatus in the G. sylvestre ecosystem.

The current study aims to assess the effectiveness of three essential oils derived from neem, citrus, and garlic against papaya mealybug. Papaya seedlings were transplanted in the field in a completely randomized block design with eight treatments with four replications. The treatments included neem, citrus, and garlic oils in combination with isopropyl alcohol or paraffin oil as an adjuvant. Results from this study showed that neem oil at 1.5% + 0.2% isopropyl alcohol was effective against papaya mealybug by 93.0% equivalent to the positive control (imidacloprid) (99.4%), followed by citrus oil at 1.5% + isopropyl alcohol (76.3%) and citrus oil at 1.5% + paraffin oil (68.8%), compared with the untreated 0.01%. Similarly, application of the plant-derived essential oils and adjuvants resulted in positive effects on plant parameters (plant height, number of leaves, flower buds, number of fruits, and fruit weight) and, hence, increased papaya yield from an average of 38 to 90 fruits/plant at first harvest. The finding from this study provides an understanding of papaya farmers towards the use of natural plant products, particularly plant-derived essential oils, and their benefits, which may encourage farmers to increase papaya production and minimize the usage of synthetic pesticides to avoid pest resistance. [ABSTRACT FROM AUTHOR]

In recent years, an invasive cassava mealybug Phenacoccus manihoti has been threatening cassava cultivation alongside another invasive papaya mealybug Paracoccus marginatus which invaded the country more than a decade ago. In order to evaluate their responses against the commonly used neonicotinoid insecticides: thiamethoxam 25 WG and imidacloprid 17.8 SL, acute toxicity experiments to determine the susceptibility baselines in populations of two invasive mealybugs in the cassava agro-ecosystem, namely, cassava mealybug P. manihoti and papaya mealybug P. marginatus were performed upto 15 generations. A systemic uptake method was used for the bioassay. The LC50 values of thiamethoxam for F1 generation were 3.298 ppm whereas it was 1.066 ppm for F15 in cassava mealybug. The LC50 values of F1 generation were 2.014 ppm and that of F15 generation was 1.384 ppm when tested with imidacloprid. In the case of papaya mealybug, the LC50 values ranged from 6.138 ppm (F1) to 2.503 ppm (F15) for thiamethoxam and 7.457 ppm (F1) to 3.231 ppm (F15) for imidacloprid. All the susceptibility indices calculated were less than threefold. The rate of resistance development was negative in all cases showing that none of the tested populations harboured any resistance without insecticidal selection pressure. Tentative discriminating doses were fixed for both chemicals with the help of LC95 values obtained from the bioassay experiments, namely five ppm for both thiamethoxam and imidacloprid in the case of cassava mealybug and 10 ppm and 15 ppm, respectively, for thiamethoxam and imidacloprid in the case of papaya mealybug. [ABSTRACT FROM AUTHOR]

Simple Summary: The papaya mealybug is a highly polyphagous invasive pest that poses a quarantine threat to tropical and subtropical countries. Infested commodities in international trade should be subject to phytosanitary treatment, and irradiation treatment is recommended to replace methyl bromide fumigation. The irradiation treatments were conducted on the gravid females and 2-, 4-, and 6-day-old eggs of Paracoccus marginatus to develop a technical schedule for phytosanitary purpose. The results showed no significant difference among gravid females and 2-, 4-, and 6-day-old eggs after exposure to a range of X-ray radiation (15–105 Gy). Moreover, the minimum radiation dose for providing quarantine security was estimated and validated in the preliminary and confirmatory tests. In the gamma radiation confirmatory tests, no nymphs emerged when a total of 60,386 gravid females were exposed to a radiation dose range of 146.8 to 185.0 Gy. Following the standard-setting principles, the largest dose value in confirmatory tests is the minimum threshold for phytosanitary treatment. As a result, we strongly recommend a minimum dose of 185 Gy for the phytosanitary irradiation of papaya mealybug-infested commodities, and the treatment efficacy is not less than 99.9950% at the 95% confidence level. Paracoccus marginatus is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade should undergo phytosanitary treatment, and irradiation is recommended as a viable alternative to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-day-old eggs and gravid females of P. marginatus using the X-ray radiation doses of 15–105 Gy with an interval of 15 Gy. Radiotolerance was compared using ANOVA, fiducial overlapping and lethal dose ratio (LDR) test, resulting in no significant difference among treatments, except for the overall mortality and LDR at LD90 (a dose causing 90% mortality at 95% confidence level). The estimated dose for LD99.9968 was 176.5–185.2 Gy, which was validated in the confirmatory tests. No nymphs emerged from a total of 60,386 gravid females exposed to a gamma radiation dose range of 146.8–185.0 Gy in the confirmatory tests. The largest dose in confirmatory tests should be the minimum threshold for phytosanitary treatment, consequently, a minimum dose of 185 Gy is recommended for the phytosanitary irradiation treatment of papaya mealybug-infested commodities, ensuring a treatment efficacy of ≥99.9950% at 95% confidence level. [ABSTRACT FROM AUTHOR]

Simple Summary: This study examined the occurrence, biological characteristics, and effectiveness of the parasitoid wasp Acerophagus papayae Noyes and Schauff in controlling the papaya mealybug Paracoccus marginatus Williams and Granara de Willink, a major pest of cassava crops in Vietnam. The results showed that A. papayae naturally occurred more frequently than other species of parasitoid wasps. The honey solution was found to be important for increasing the lifespan of A. papayae in the absence of hosts. The second instar of the mealybug was found to be the most suitable host stage for parasitism by A. papayae. Female wasps can produce a large number of eggs during their entire lives. These findings suggest that A. papayae could be an effective agent for controlling P. marginatus and improving crop pest management not only in Vietnam, but in other regions as well. Cassava is a valuable export commodity crop that is often attacked by pests, causing economic losses for this crop. The papaya mealybug Paracoccus marginatus has become a major pest of cassava in Vietnam. The parasitoid wasp Acerophagus papayae has been demonstrated to be the most efficient parasitoid wasp for controlling P. marginatus in many regions. We observed the occurrence of A. papayae in Vietnam, studied the biological characteristics of A. papayae, and investigated its parasitic activity on P. marginatus. The results showed that A. papayae occurred more frequently than Anagyrus loecki, another known parasitoid of P. marginatus. The lifespan of A. papayae was approximately 16 days. In the absence of hosts, a 50% honey solution was an essential diet to increase the longevity of both female and male of A. papayae. The second instar of P. marginatus was a suitable host stage for parasitism by A. papayae. Female A. papayae laid approximately 60.8 eggs within 17 days, mostly during the first 6 to 7 days. These findings suggest that A. papayae has the potential to control P. marginatus, and could inform the development of more effective pest management strategies for cassava crops in Vietnam and other regions affected by this pest. [ABSTRACT FROM AUTHOR]

Paracoccus marginatus papaya mealybugs cause considerable threats and challenges to cassava production and processing. The deployment of resistant cultivars offers effective, economical and eco-friendly management strategies for pest management. We measured P. marginatus mortality, development and reproduction to evaluate the resistance of fifteen cassava cultivars and conducted physiological and biochemical analyses when P. marginatus was fed on two resistant cultivars (Myanmar and C1115) and three susceptible cultivars (BRA900, Bread, SC205). Significantly lower digestive (amylase, sucrase, lipase), detoxification (glutathione-S-transferase and carboxylesterase) and antioxidant activity, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO), enzyme activities were observed in P. marginatus feeding on resistant cultivars compared to susceptible cultivars. For resistant cultivars, a significant reduction was found in nutritional components containing free amino acids, nitrogen, soluble sugars and the secondary metabolite malondialdehyde. Additionally, significantly higher enzymatic activity (SOD, CAT, POD and PPO) levels and secondary metabolite quantities (total phenol and tannins) were found in resistant cultivars induced by P. marginatus compared with susceptible ones. Additionally, RT-qPCR tests showed that the transcripts of ten genes involved in nutrition, secondary metabolites and antioxidant activities were consistent with physiology changes. Thus, the resistant cultivars suffered lower P. marginatus damage by elevating secondary metabolite contents and antioxidant activities, reducing plant nutrition levels and decreasing insect enzymatic activities. This study will be beneficial in developing indices for standard regulation to evaluate P. marginatus-resistant cassavas and effectively manage this pest. [ABSTRACT FROM AUTHOR]

Simple Summary: Papaya mealybug, Paracoccus marginatus, is an important invasive pest worldwide, which attacks more than 200 host plants. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. To evaluate the long-term sublethal effects of chlorfenapyr on P. marginatus, the sublethal and transgenerational effects of chlorfenapyr on the biological traits and changes of enzyme activities of P. marginatus were investigated. The results showed that chlorfenapyr had significant effects on the development of subsequent generations of P. marginatus, and chlorfenapyr also activated the activities of SOD of P. marginatus. The results demonstrated that chlorfenapyr-mediated sublethal effects occur in at least two successive generations of P. marginatus. Therefore, it is necessary to reapply the chlorfenapyr prior to emergence of the F3 generation to suppress the population and prevent outbreaks of P. marginatus. Papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is an economically important, invasive insect that is now distributed worldwide. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. In order to evaluate the sublethal and transgenerational effects of chlorfenapyr on P. marginatus, the life table data of three consecutive generations were collected and analyzed by the age stage, two-sex life table method, and the enzyme activities were assayed using a spectrophotometer. The results showed that exposure to the insecticide had significant effects on the biological traits of subsequent generations of P. marginatus, and a higher intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and a shorter mean generation time (T) were observed in the chlorfenapyr-treated F1 mealybugs. Enzyme activity assays showed that chlorfenapyr significantly inhibited the activities of catalase (CAT) and peroxidase (POD) while activating the activities of superoxide dismutase (SOD), which suggested that SOD, CAT, and POD may play an important role in the self-defense of P. marginatus against chlorfenapyr. These results conclusively demonstrated that exposure of P. marginatus to sublethal concentrations of chlorfenapyr induced hormetic effects on the F1 generation while having negative effects on the F0 and F3 generations. [ABSTRACT FROM AUTHOR]

The papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), poses a serious threat to global trade and is classified as a quarantine pest in some countries. Phosphine (PH3) is considered an alternative to methyl bromide for postharvest control of P. marginatus. However, reports addressing the impact of PH3 treatment to control P. marginatus on succulent plants are lacking. This study aims to investigate the effects of PH3 fumigation alone and in combination with ethyl formate (EF) on insecticidal activity across all developmental stages of P. marginatus and its influence on the quality of plant products. Tolerance tests showed that among all developmental stages, the egg stage of P. marginatus is the most tolerant to PH3 treatment. A concentration of 1 g m-3 PH3 for 8 h exposure at 25 °C achieved a 99.9968% (Probit-9) mortality rate for the eggs. Additionally, we examined the synergistic effects of combining EF with PH3. Combined fumigation with 0.5 g m-3 PH3 and 2 g m-3 EF for 8 h at 25 °C did not adversely affect the lifespan and quality of three succulent plant species, achieving an effective dose of 0.99991. These findings suggest that PH3 fumigation, with or without EF, are effective treatments for postharvest control of P. marginatus in succulent plants., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Paracoccus marginatus is a highly polyphagous invasive pest that poses a significant quarantine threat to tropical and subtropical countries. Infested commodities in international trade should undergo phytosanitary treatment, and irradiation is recommended as a viable alternative to replace methyl bromide fumigation. Dose-response tests were conducted on the 2-, 4-, and 6-day-old eggs and gravid females of P. marginatus using the X-ray radiation doses of 15–105 Gy with an interval of 15 Gy. Radiotolerance was compared using ANOVA, fiducial overlapping and lethal dose ratio (LDR) test, resulting in no significant difference among treatments, except for the overall mortality and LDR at LD90 (a dose causing 90% mortality at 95% confidence level). The estimated dose for LD99.9968 was 176.5–185.2 Gy, which was validated in the confirmatory tests. No nymphs emerged from a total of 60,386 gravid females exposed to a gamma radiation dose range of 146.8–185.0 Gy in the confirmatory tests. The largest dose in confirmatory tests should be the minimum threshold for phytosanitary treatment, consequently, a minimum dose of 185 Gy is recommended for the phytosanitary irradiation treatment of papaya mealybug-infested commodities, ensuring a treatment efficacy of ≥99.9950% at 95% confidence level.

Fitness of the Papaya Mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), after Transferring from Solanum tuberosum to Carica papaya, Ipomoea batatas, and Alternanthera philoxeroides Keywords: Paracoccus marginatus; host plant shifting; two-sex life table; fitness EN Paracoccus marginatus host plant shifting two-sex life table fitness N.PAG N.PAG 16 09/27/22 20220901 NES 220901 1. The age-stage reproductive value ( I v SB xj sb i ), which represents the contribution of each individual in age I x i and stage I j i makes to the future population [[25]], was calculated as: HT ht 2.5. [Extracted from the article]

Purpose: Considering the predatory effectiveness of Chrysoperla carnea (Neuroptera: Chrysopidae), studies were carried out at National Agricultural Research Centre, Islamabad, Pakistan to determine the feeding potential and developmental period of its larval instars on Paracoccus marginatus (Hemiptera: Pseudococcidae). Research Method: Eggs, 1st, 2nd, and 3rd nymphal instars and adults of P. marginatus were provided to all three larval instars of C. carnea in a Completely Randomized Design experiment, replicated ten times. Findings: Results indicated that all C. carnea larval instars were found to feed on all P. marginatus stages. Overall mean consumption of C. carnea larvae on P. marginatus eggs, 1st, 2nd and 3rd instar nymphs, and adults was 1359.8, 1409.1, 1012.4, 1165.7 and 130.30 individuals, respectively. Third instar C. carnea larvae were more voracious than 2nd and 1st instars. The shortest developmental period (12.40±0.37 days) of C. carnea larvae was recorded on 3rd nymphal instar of P. marginatus. Moreover, C. carnea larvae took 14.90±0.23, 14.00±0.25, 13.10±0.23, and 13.60±0.34 days on eggs, first, second nymphal instars and adults of P. marginatus, respectively to complete their development. Originality/Value: Therefore, it is suggested that C. carnea should be included as a key component in the integrated management of P. marginatus, especially its 3rd larval instar. [ABSTRACT FROM AUTHOR]

Cassava is one of the most produced food materials and constitutes the major energy source for about 800 million people worldwide. Mealybugs have been reported to be the main concern in cassava production for the past few years in all the major tuber cultivated ecosystems of India. Endosymbiotic bacteria found in mealybugs have been observed to interact and provide specific advantages to the host and they can be one of the reasons for the pests' insecticidal resistance. In the present study, endosymbiotic bacteria were isolated from cassava mealybugs, allowed to grow in media after insecticidal treatments, and after observing colony morphology, distinct bacterial colonies were sub-cultured and selected for further molecular identification procedures. PCR analysis was carried out for bacteria using 16S rRNA primer, with an annealing temperature of 49°C, and yielded fragments at 1500 bp. Based on the sequencing report, the observations were that the culturable endosymbionts Pseudomonas oryzihabitans, Staphylococcus sp. which are resistant to the insecticide thiamethoxam are present in Paracoccus marginatus, and malathion resistant Paenibacillus alvei, Ralstonia sp., and thiamethoxam resistant Clostridium lundense are present in Ferrisia virgata. The sequences were submitted to NCBI, and the accession numbers obtained were OP572218, OP572193, OP572215, OP572194, and OP572097, respectively. Also, through diagnostic PCR using specific bacterial primers, the presence of Wolbachia is confirmed in mealybug F. virgata at a fragment length of 650 bp. [ABSTRACT FROM AUTHOR]

Cassava is a valuable export commodity crop that is often attacked by pests, causing economic losses for this crop. The papaya mealybug Paracoccus marginatus has become a major pest of cassava in Vietnam. The parasitoid wasp Acerophagus papayae has been demonstrated to be the most efficient parasitoid wasp for controlling P. marginatus in many regions. We observed the occurrence of A. papayae in Vietnam, studied the biological characteristics of A. papayae, and investigated its parasitic activity on P. marginatus. The results showed that A. papayae occurred more frequently than Anagyrus loecki, another known parasitoid of P. marginatus. The lifespan of A. papayae was approximately 16 days. In the absence of hosts, a 50% honey solution was an essential diet to increase the longevity of both female and male of A. papayae. The second instar of P. marginatus was a suitable host stage for parasitism by A. papayae. Female A. papayae laid approximately 60.8 eggs within 17 days, mostly during the first 6 to 7 days. These findings suggest that A. papayae has the potential to control P. marginatus, and could inform the development of more effective pest management strategies for cassava crops in Vietnam and other regions affected by this pest.

Mealybug is an important pest of papaya plants. Induction of plant resistance using elicitors, such as salicylic acid, might have the potency to reduce the extent of crop damage by mealybug. Therefore, a laboratory experiment was performed to determine the effect of salicylic acid on feeding preference, fecundity, oviposition period, and longevity of papaya mealybug adult, Paracoccus marginatus. The results showed that the application of salicylic acid increased total phenol content on papaya leaf (r = 0.57) hence decreased in feeding preferences and fecundity, slowed down the growth period of the nymph and pre-oviposition period, and prolonged the longevity of mealybug. The potency of using salicylic acid to control of mealybug on papaya in integrated pest management was discussed in this paper.

Aspects of biology of Acerophagus papayae Noyes & Schauff (Hymenoptera: Encyrtidae), parasitoid of papaya mealybug. Acerophagus papayae Noyes & Schauff (Hymenoptera: Encyrtidae) is an important parasitoid of the papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae). The study was conducted with the objective to determine various aspects of the biology of A. papayae which include the effect of diet on adult longevity, fecundity and progeny, host stage susceptibility and preference, the effect of host stages on immature development, body size, and sex ratio of progenies. Effects of diet on adult longevity was done in the absence of hosts. Fecundity was measured by the number of mealybugs parasitized. Host stage susceptibility and preference were carried out by exposing 2nd and 3rd nymphal instars and pre-reproductive adults of mealybugs to parasitoids. Results showed adult parasitoids fed with 10% honey solution lived almost fourfold longer than those provided only water. A. papayae parasitized 30.1±4.92 mealybugs, with a range of 13-60 mealybugs, during 5.8 days of adult life. In no-choice (susceptibility) and paired-choice (preference) tests, the percentage of parasitized hosts were significantly greater in 2nd and 3rd instar nymphs than in adults. The mean immature developmental time of A. papayae was longer when the parasitoids develop in large host. Developmental time of male parasitoids was shorter than the females. Female wasps which emerged from hosts parasitized at the 3rd instar nymphs and adults were significantly larger than those from the 2nd instar nymphs. Sex ratios of the offspring emerged from hosts that were parasitized as 2nd instars were strongly male-biased, while the later stages yielded more females than males.

Papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is an economically important, invasive insect that is now distributed worldwide. Chlorfenapyr has been demonstrated to have a significant control effect on P. marginatus. In order to evaluate the sublethal and transgenerational effects of chlorfenapyr on P. marginatus, the life table data of three consecutive generations were collected and analyzed by the age stage, two-sex life table method, and the enzyme activities were assayed using a spectrophotometer. The results showed that exposure to the insecticide had significant effects on the biological traits of subsequent generations of P. marginatus, and a higher intrinsic rate of increase (r), finite rate of increase (λ), net reproductive rate (R0), and a shorter mean generation time (T) were observed in the chlorfenapyr-treated F1 mealybugs. Enzyme activity assays showed that chlorfenapyr significantly inhibited the activities of catalase (CAT) and peroxidase (POD) while activating the activities of superoxide dismutase (SOD), which suggested that SOD, CAT, and POD may play an important role in the self-defense of P. marginatus against chlorfenapyr. These results conclusively demonstrated that exposure of P. marginatus to sublethal concentrations of chlorfenapyr induced hormetic effects on the F1 generation while having negative effects on the F0 and F3 generations.

The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is a polyphagous invasive pest in China. The effect that the shifting of the host plant has on the fitness of a polyphagous pest is critical to its prevalence and potential pest control. In order to assess the fitness changes of P. marginatus after transferal from potato (Solanum tuberosum (Tubiflorae: Solanaceae)) to papaya (Carica papaya (Parietales: Caricacea)), sweet potato (Ipomoea batatas (Tubiflorae: Convolvulaceae)), and alligator weed (Alternanthera philoxeroides (Centrospermae: Amaranthaceae)), the life table data of three consecutive generations were collected and analyzed using the age-stage, two-sex life table method. The results showed that when P. marginatus was transferred from S. tuberosum to papaya, a higher intrinsic rate of increase (r) and finite rate of increase (λ) were observed. Paracoccus marginatus individuals transferred to I. batatas had the significantly lower population parameters than those on C. papaya; however, the fitness recovered for those on I. batatas after two generations. Paracoccus marginatus individuals were unable to complete development on A. philoxeroides. Our results conclusively demonstrate that P. marginatus individuals can readily adapt to C. papaya and I. batatas even after host plant shifting, and are capable of causing severe damage to these hosts.

The papaya mealybug (PM) is a known notorious polyphagous insect pest of many plant species and has always been found associated with a new host/s in newly invaded areas. This pest recently invaded West and Central Africa. Surveys were conducted randomly from July 2014 to May 2018 to determine the host range of this pest in the Center and Littoral regions in Cameroon. Plants infested by PM were recognized by the presence of black sooty mould, leaf deformation and/or chlorosis. A standard infestation scale was used to evaluate the infestation level on each plant. After collection, infested plants were pressed, dried and identified at the national Herbarium. A total of 52 plant species (only one undetermined) belonging to 23 families were found infested by PM associated with other mealybug or with two species of mealybugs with a percentage of (79.2%, N = 75) and (20.8%, N = 75) respectively. Two plant families (out of 23 identified) and 18 plant species (out of 52 infested) were reported as host plants for the first time. The Euphorbiaceae, Malvaceae and Solanaceae are the most infested families. In addition to plant species from its native zone (tropical America), PM has established new associations with plants from tropical Africa. Carica papaya and ten additional plants were categorized as favored hosts of P. marginatus. These results will be very useful to develop appropriate management options for PM in West and Central Africa. [ABSTRACT FROM AUTHOR]

The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Coccomorpha: Pseudococcidae) is an invasive insect pest of Central American origin that has become a serious threat to about 60 plant species belonging to more than 22 families across the globe. The average life cycle of P. marginatus lasts between 15–32 days depending on host plant species and it can complete about 11–13 generations per year, depending on the temperature and relative humidity. It is of considerable economic importance and causes major losses to both agricultural and horticultural crops. In India, papaya mealybug became a major pest in 2009 with a devastating outbreak in south India. Even though several control methods, such as cultural, chemical, legal and biological control, have been adopted to tackle the problem, only chemical and biological control methods have been widely practised for its management. About 17 predators and 8 host specific parasitoids have been reported to give effective control of P. marginatus. However, the parasitoid Acerophagus papayae Noyes and Schauff (Hymenoptera: Encyrtidae) has played a predominant role in suppressing P. marginatus, with percentage parasitism in several countries between 75–81%. Owing to papaya mealybugs' polyphagy, wide climatic adaptability and ecological plasticity, it clearly has the potential to invade new areas and host plants and is likely to cause much damage in the future. In this paper, the origin, distribution, taxonomy, bio-ecology, host range, natural enemies, management practices and the possible effects of climate change on P. marginatus are critically reviewed. The information gathered will guide the management of this difficult to control insect pest.

The present study was conducted to characterize the newly invasive papaya mealybug Paracoccus marginatus Williams and Granara de Willink in Kenya using molecular techniques and to establish the potential risk of spread of the pest. Although abundant literature of P. marginatus outbreaks exists in other parts of the world, studies from Africa are rare. Our results revealed significant similarity between Kenyan samples with GenBank accession number KP692333.1 of P. marginatus. Phylogenetic analyses generated a tree that was paraphyletic with two clusters showing low genetic distance values for the P. marginatus sequences, which diverged from that of Planococcus citri. Our models displayed an optimal performance with mean area under the curve value of 0.82 and 0.98 for Genetic Algorithm for Rule‐Set Production (GARP) and maximum entropy modelling (MaxEnt), respectively. Isothermality was the most influential variable in determining the potential distribution of P. marginatus with a 69% contribution to the models. Other variables included temperature mean diurnal range temperature seasonality, temperature annual range and annual precipitation in decreasing order of contribution. Current prediction by both models exceeded the existing range of P. marginatus, exacerbating the potential threat of the pest. GARP was more conservative in predicting suitable areas for P. marginatus, while MaxEnt showed further expansion by the year 2050. Our findings provide important information to guide biosecurity agencies in decision‐making to prevent the spread and enhance control efforts of P. marginatus. [ABSTRACT FROM AUTHOR]

The effects of spray adjuvants on physical properties of two insecticides and the synergistic effects against Paracoccus marginatus were investigated in this study. The effects of surface tension, expanded diameter, maximum retention on spirodiclofen 240 g/L suspension concentrate(SC) and pyridaben 15% emulsifiable concentrate(EC) were determined under indoor conditions after the addition of five spray adjuvants (aloe essential oil, silicone silwet408, JFC-2, azone and PBO). In addition, the synergistic effect between the adjuvants and two insecticides were evaluated. The results indicated that the spray adjuvants can significantly reduce the surface tension, increase the expansion diameter, retention and indoor virulence. Spray adjuvants can increase the indoor virulence of spirodiclofen 240 g/L SC and pyridaben 15% EC by 5.1%-26.1% and 22.7%-41.8%, respectively. JFC-2 and PBO were more effective for the increase of the synergistic effects with spirodiclofen 240 g/L SC and pyridaben 15% EC. Field experiments showed that JFC-2 and PBO improved the field control effect of two insecticides in different concentrations against P. marginatus, especially for that in high concentrations. The synergistic effect between JFC-2 and spirodiclofen 240 g/L SC was 10.3%-24.6%, and that between PBO and pyridaben 15% EC was 12.1%-28.9%. [ABSTRACT FROM AUTHOR]

Biology and life table of papaya mealybug Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) on three host plant species. The papaya mealybug, Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae), has been considered as a new invasive pest causing heavy damage on papaya in Indonesia since 2008. The pest is polyphagous with more than 55 host plant species. Study was conducted in laboratory with the objectives to determine developmental biology and life table parameters of the mealybug feeding on papaya, physic nut, and cassava leaves. Host plant species affected papaya mealybug performances. Egg stage lasted 7.25, 8.09, and 9.86 d on papaya, physic nut, and cassava, respectively. The shortest female nymphal developmental time was on papaya (18.91 d) and the longest on cassava (32.45 d). Longevity of adult males ranged from 1.09-2.85 d while females 12.29-14.93 d. When the mealybugs were reared on a seedling, the fecundity was higher on papaya (324.6) than those on physic nut (186.6) and cassava (157.5). No egg production occurred in virgin females. The sex ratio of P. marginatus favoured females, which comprised about 90% of population on papaya and cassava. The intrinsic rate of increase (rm) was significantly different among hosts, with the highest rate (0.117 female offspring/female/d) on papaya, followed by physic nut (0.079) and cassava (0.057). The maximum values of rm along with net reproductive rate (Ro) and finite rate of increase(λ), and the shortest mean generation time (T) and doubling time (Dt) on papaya, indicating that papaya was the more favorable host plant for P. marginatus.

Populations and damage by the papaya mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae) on papaya inlowland areas of South Sumatera. One of the main problems in papaya cultivation today is the presence of a newlyintroduced pest, the white papaya mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae). This study aimed toobserve the mealybug populations and its damage percentage in papaya plants and to identify its host plants in SouthSumatera. The study was carried out on the fruit and vegetable producing area in Indralaya, South Sumatera. The survey wasconducted on papaya plantation plots with a minimum size of 1000 m2. Data from the observation indicated that populationsof P. marginatus on papaya fruit were not significantly different to those on papaya leaves, except for the first observation inthe rainy season. In general, the percentages of mealybug damages were not affected by the season and the percentages ofdamage on the leaves were not different from those on the fruits of the papaya plants. Inventory of P. marginatus host plantson the area resulted in a total of 12 species of host plants dominated by dicotyledonous plant species. The host plants werefrom 11 families, i.e. Anacardiaceae, Caricaceae, Cucurbitaceae, Euphorbiaceae, Fabaceae, Myrtaceae, Rosaceae, Rutaceae,Sapindaceae, Sapotaceae, and Solanaceae.

The cotton mealybug, Phenacoccus solenopsis Tinsley and papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) are becoming major threats to the production of Gymnema sylvestre R. Br. (Asclepiadaceae) in India. Management mainly depends on chemical insecticides which cause a serious problem of pesticide residue and insecticide resistance. The use of biorational insecticides such as biopesticides, botanicals, insect growth regulators, and microbial insecticides is important components of an Integrated Pest Management (IPM) program for successful management. We evaluated the bio-efficacy of twelve biorational insecticides, including entomopathogenic fungi (EPF), using the leaf spray method in laboratory conditions at 25 ± 1 °C, 70 % ± 5 % RH. The results revealed that the highest percent mortality was recorded by acetamiprid 20 % SP (100.00 %), followed by azadirachtin (98.27 %), Lecanicillium muscarium (2 × 10 9 spores/mL) (85.70 %) and Ocimum sanctum leaf extract (76.87 %) at 120 h after treatment (HAT) in P. solenopsis . In P. marginatus , 100.00 %, 96.39 % and 85.67 % and 74.90 % mortalities were achieved by acetamiprid 20 % SP, azadirachtin, L. muscarium (2 × 10 9 spores/mL) and O. sanctum leaf extract, respectively, at 120 HAT during the first spray. Various biorational insecticides showed a more or less similar trend of percent mortality in both species during the second spray. In both species, the lowest percent mortality was recorded by Andrographis paniculata leaf extract (46.29, 44.54) and (41.03, 46.39) at 120 Hours after treatment in the first and second spray, respectively. It was concluded that all the prescribed treatments are more effective than the control. Overall, azadirachtin recorded the highest percent mortality after acetamiprid and had the shortest LT 50 (12.52 h) and (13.87 h) values in P. solenopsis and P. marginatus , respectively. Our study emphasizes that biopesticides like Azadirachtin 1 % EC (10000 ppm), L. muscarium (2 × 10 9 spores/mL) (5 mL/L) and O. sanctum leaf extract (5 %) may be recommended as alternatives to synthetic insecticides. Botanicals and EPF would be the most effective approach for sustainable integrated management of P. solenopsis and P. marginatus in the G. sylvestre ecosystem., Competing Interests: The authors declare that they have no conflict of interest., (© 2023 The Authors. Published by Elsevier Ltd.)

Acerophagus papayae is a koinobiont endoparasitoid of the invasive papaya mealybug, Paracoccus marginatus and has been introduced as a classical bio-control agent of the mealybug in many countries. Considering the importance, parasitism efficiency of A. papayae against various life stages of P. marginatus was conducted in choice experiments. Results suggested that A. papayae showed higher parasitism efficiency towards third instar female nymphs and adult female P. marginatus in comparison to second instar male. However, second instar male nymphs were more preferred in comparison to second instar female nymphs. Acerophagus papayae exhibited a highly significant sex-biased development ratio as a female dominant progeny emerged while feeding on female hosts and vice versa. No difference was recorded in the developmental time of male and female A. papayae, however, females matured one day later than males. The only gregarious behaviour of A. papayae was recorded on adult female P. marginatus as more than one adult parassitoid emerged from a single host. Study results suggested that A. papayae has a tremendous potential to be utilized in classical biological control programs against P. marginatus as it showed more preference towards female hosts; hence not only reducing available pest population but also will affect the pest population of next generation. [ABSTRACT FROM AUTHOR]

This study was conducted in 2015-16 to assess the role of maintaining natural enemies field reservoir (NEFR) for controlling papaya mealy bug Paracoccus marginatus William and Granara de Willink. The NEFR was established at Memon Goth- Karachi in a papaya field about a hectare. A shelter was provided alongside the border of papaya orchard where field collected mealy bug infested farm debris were kept in open trays for 15 days. From debris thousands of parasitoid Acerophagus papayae Noyes and Schauff and generalists associated with mealy bug could be produced almost around the year. The parasitoid and the predators produced from mealy bug infested farm debris under NEFR shelter could naturally disperse into the environment around. Dispersal range of A. papayae was followed both in direction of sea side winds from NEFR and in opposite direction. Dispersal of the parasitoid and the predators was found more convenient to fields from NEFR in direction of sea side winds where dense colonies of the mealy bug became rare because of increase in parasitism in the mealy bug and increase in number of predators numbers. On opposite direction of the winds mealy bug dense colonies were encountered and less parasitism. [ABSTRACT FROM AUTHOR]