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Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) is a sporadic pest of cotton and several other agricultural crops. The expansion of insecticide resistance has compelled the assessment of chemically novel insecticides. Therefore, the lethal effects of systemic insecticides, flonicamid 50 WG (pyridincarboxamide) and spirotetramat 240 SC (ketoenole) were assessed against different life stages (egg, nymph, pupae and adult) of B. tabaci in the laboratory. The sublethal effects of these insecticides in relation to life table parameters of B. tabaci were also investigated. Spirotetramat was most effective against all nymphal instars and pupae but was relatively less toxic against adult stage of B. tabaci compared to flonicamid. Whereas, flonicamid was highly effective against adult, less effective against nymph and least effective against pupae in comparison to the efficacy of spirotetramat. Flonicamid and spirotetramat possessed weak ovicidal potential at all different tested concentrations. LC50 values (72.96, 76.14 and 85.51 ppm) revealed two-fold toxicity of spirotetramat as compared to LC50 values (123.40, 133.43 and 178.56 ppm) of flonicamid against 1st, 2nd and 3rd instar-nymph, respectively. Flonicamid was 54 folds more toxic against B. tabaci adults with LC50 value of 3.99 ppm than that of spirotetramat (218.36 ppm). With sublethal concentration of flonicamid and spirotetramat, the intrinsic rate of increase of population per day (r = 0.080 and 0.093, respectively) and estimated finite rate of increase in population (λ = 1.083 and 1.097, respectively) were considerably decreased than control (r = 0.157 and λ = 1.170). However, the values of life table parameters (r and λ) were significantly smaller after exposure of flonicamid than spirotetramat. The net reproductive rate (R0= offspring/ female) and mean generation time (T = days) of female B. tabaci were significantly reduced (7.085 and 21.03, respectively) with spirotetramat than those of flonicamid (40.88 and 46.11, respectively). Flonicamid extended the developmental duration of immature stages and the emergence of female and male (sxj: 34 and 39 days, respectively) compared to Spirotetramat. Spirotetramat significantly decreased the rate of age stage survival (lx), age-stage specific fecundity (fxj), age-specific fecundity (mx) and age-specific maternity (lxmx) compared to flonicamid and control treatment. The male and female treated with spirotetramat survived (life expectancy: exj) longer (47 and 37 days, respectively) than flonicamid (26 and 12 days, respectively). The least vxj reproductive curve for females was observed with spirotetramat (11.83) at 16th day compared with control (24.46) at 16th day and the highest with flonicamid (66.50) at 35th day of age. This study is the first stride towards establishing a scientific base for the efficient use of tested insecticides for pest control. [ABSTRACT FROM AUTHOR]

Transgenic technology played a crucial role in developing insect-resistant plants resulting in the reduced application of pesticides. This article reports the expression of two cry proteins (Cry3Bb1 and Cry3) in cotton for enhanced resistance against chewing insect pests. The aforementioned genes were synthetically developed and were cloned under appropriate regulatory sequences followed by transformation into Eagle-2 genotype (Gossypium hirsutum) of cotton through shoot apex-cut Agro-infiltration. The transgene integration was validated by polymerase chain reaction using primers flanking the aforementioned cry genes. Transgene expression was assessed by qRT-PCR using GADPH as a reference gene. The relative fold expression analyses revealed the highest expression of the transgene(s) in M1 plants, which is a 4.5-fold expression (Cry3 + Cry3Bb1) followed by M3 (fold expression, 3.0) (Cry3Bb1) and M2 (fold expression, 2.5) (Cry3) transformants of cotton. The confirmed transgenic plants were exposed to insect pests, pink bollworm (Pectinophora gossypiella), and army bollworm (Helicoverpa armigera). Bioassay results revealed that 60% mortality was observed against pink bollworm, and 75% mortality was observed against army bollworm in transgenic plants containing both Cry3Bb1 and Cry3 genes (M1 transgenic plants). In M2 transgenic plants containing only the Cry3Bb1 gene, the mortality was observed to be 40% in the pink bollworm population, whereas 45% mortality was observed in the army bollworm population. In the case of M3 transgenic plants containing single gene-Cry3, the mortality was 20% in the pink bollworm population, whereas 30% mortality was observed in the army bollworm population. Almost no mortality was observed in non-transgenic Eagle-2 control plants. Hence, the developed cotton transformants have improved resistance against chewing insect pests. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) triggered by exogenous double-stranded RNA (dsRNA) is a powerful tool to knockdown genetic targets crucial for the growth and development of agriculturally important insect pests. Helicoverpa armigera is a pest feeding on more than 30 economically important crops worldwide and a major threat. Resistance to insecticides and Bt toxins has been gradually increasing in the field. RNAi-mediated knockdown of H. armigera genes by producing dsRNAs homologous to genetic targets in bacteria and plants has a high potential for insect management to decrease agricultural loss. The acetylcholinesterase (AChE), ecdysone receptor (EcR) and v-ATPase-A (vAA) genes were selected as genetic targets. Fragments comprising a coding sequence of < 500 bp were cloned into the L4440 vector for dsRNA production in bacteria and in a TRV-VIGS vector in antisense orientation for transient expression of dsRNA in Solanum tuberosum leaves. After ingesting bacterial-expressed dsRNA, the mRNA levels of the target genes were significantly reduced, leading to mortality and abnormal development in larva of H. armigera. Furthermore, the S. tuberosum plants transformed with TRV-VIGS expressing AChE exhibited higher mortality > 68% than the control plants 17%, recorded ten days post-feeding and significant resistance in transgenic (transient) plants was observed. Moreover, larval lethality and molting defects were observed in larva fed on potato plants expressing dsRNA specific to EcR. Analysis of transcript levels by quantitative RT–PCR revealed that larval mortality was attributable to the knockdown of genetic targets by RNAi. The results demonstrated that down-regulation of H. armigera genes involved in ATP hydrolysis, transcriptional stimulation of development genes and neural conduction has aptitude as a bioinsecticide to control H. armigera population sizes and therefore decreases crop loss. [ABSTRACT FROM AUTHOR]

Guava is one of the most popular fruits in the world by its taste and nutritional value. In Pakistan, it is the third most rapidly growing fruit. The peach fruit fly, Bactrocera zonata is one of the major hindrances in the yield and productivity enhancement of fruits. The entomopathogenic fungi are considered an effective managemental practice against fruit flies. In order to estimate the efficiency of two species of fungi, Beauveria bassiana and Metarhizium anisopliae were tested at concentrations of conidia, 1x108, 1x107 and 1x'06 against adults of B. zonata in the laboratory conditions. The mortality was recorded after 7 and 15 days of treatment. Both fungal species were found significant at the concentration of 1x108. For B. bassiana mortality observed were 40% and 43.33% at the interval of 7 and 15 days respectively, on the concentration of 1x108 conidia/ml. While M. anisopliea showed 35% and 40% mortality against adults of B. zonata. The use of EPF in IPM plans can lead to effective management against fruit fly since there is a need for sustainable and environmentally safe practices in fruit farming. [ABSTRACT FROM AUTHOR]

Current study was conducted to check the efficacy of different zinc phosphide formulations (Hit rat + crushed wheat, hit rat + sweat, ractophos + crushed wheat and ractophos + sweat) in the form of baits, Agtoxin and ultrasonic repellant devices against rats in a sugarcane field. Experiments were conducted in field area of sugarcane crop in Chak No. 33 J.B. Faisalabad, Pakistan for two consecutive years 2017 and 2018. The crop was sown in February, while treatments were applied from June to October. Data regarding the number of burrows was taken in November, while tile activity was recorded on a fortnight basis. The yield was recorded at the crop harvest. The efficacy was calculated in the form of reduction in number of burrows, decrease in infestation, decrease in sugarcane yield and recording the activity of rats on tiles placed in sugarcane fields. Results revealed that highest reduction in a number of burrows was found in agtoxin (96.25%) and then in hit rat + crushed wheat bait application (87.54%), while a lowest reduction in a number of burrows was observed in the ultrasonic repellant device (58.73%). The highest decrease in infestation was observed in hit rat + crushed wheat treatment (84.21%) while the lowest was in the ultrasonic devices (40.23%). The highest yield of sugarcane was recorded in hit rat + crushed wheat (943.14 M/acre) while the lowest was in the ultrasonic repellant device (853.05 mond/acre). Minimum rat activity was observed in Hit rat and crushed wheat treatment while maximum in repellant device treatment in both the years in tile experiment. The present study results indicated that Hit rat + crushed wheat treatment proved best among all the treatments. The yield of sugarcane can be enhanced and infestation of sugarcane by rats can be reduced by the use of this application treatments, which will enhance the profit of sugarcane farmers. [ABSTRACT FROM AUTHOR]

The herein reported studies were conducted to investigate the insecticidal effect of seven insect growth regulators, viz., lufenuron 50 EC, flufenoxuron 10 DC, pyriproxyfen 10.8 EC, tebufenozide 20 SC, methoxyfenozide 240 SC, triflumuron 20 SC, and buprofezin 25% WP against pupal and adult suppression of Trogoderma granarium (Everts) and Tribolium castaneum (Herbst). The results about the effect of IGRs on subsequent stages after larvae indicated that all the treatments had significant impact on pupation, which escalated with an increase in concentration and exposure period. Results revealed that adult suppression was highest due to the flufenoxuron and lowest in triflumuron. Results revealed that after 7 days the lowest pupation suppression (38.18%) was observed at 2.5 ppm followed by 44.92% at 5 ppm concentrations and the pupation inhibition was highest 55.88% at 10 ppm against T. granarium. The pupation inhibition percentage in T. castaneum was highest 65.70% at 10 ppm and lowest at 2.5 ppm with value 47.85% after 7 days of treatment application. Results revealed that after 7 days the lowest adult suppression (44.63%) was observed at 2.5ppm followed by 51.42% at 5 ppm concentrations and the adult suppression was highest 62.42% at 10 ppm against T. granarium. The adult suppression percentage in T. castaneum was highest 75.61 % at 10 ppm and lowest at 2.5 ppm with value 57.91%after7 days of treatment application. Bioactivities of all the tested IGRs were found to be dose and exposure period dependent. All the IGRs are more persistence and effective when applied on wheat, than on rice and maize. From these results, it is concluded that the applications of IGRs have proved to be very effective against both species examined in the present study. These compounds particularly CSis (flufenoxuron, lufenuron and triflumuron) should be considered as potential components in IPM of stored grains insects pests. [ABSTRACT FROM AUTHOR]

Plutella xylostella is a globally distributed polyphagous pest of cruciferous crops causing 50 to 80% crop losses annually. The management generally depends on chemical control, however due to occurrence of resistance to major insecticidal groups alternative approaches are inevitable. Microbial control using Entomopathogenic fungi i.e.Beauveria bassiana has potential to suppress the insect population. In the current study 5 serial dilutions of B.bassiana spores were tested by using two different methodologies against 2nd and 3rd instar larvae of P. xylostella. Results revealed that there exists a significant difference between the two methodologies. Direct foliar application causes maximum mortality in both 2nd and 3rd instar larvae. Maximum mean corrected pathogenicity 96.6% was caused by fungal spores when 1 × 108 concentration was sprayed directly on 2nd instar larvae as compared to leaf dip method. In case of third instar larvae also the direct application was most effective induces 70% corrected mortality. This information will help to adopt appropriate method for fungal application in case of insect pest management. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis transgenic cotton, is being a vital part of a pest management program, effectively controlling Helicoverpa armigera. However, the success of Bt technology depends on the persistent susceptibility of target pests to the Bt cotton. In this respect, bioassays were conducted on laboratory reared H. armigera population (1st, 2nd, 3rd, 4th and 5th instar) fed with detached plant leaves, square, flowers, bolls. The results exhibited that first and second instars were most susceptible showing highest percent mortality on leaves > square > flower > bolls of dual toxin genotype CEMB 33 followed by single Bt cotton genotypes (FH-118 > FH-Lalazar > MNH-886 > FH-142, respectively). The third instar was moderately susceptible on all detached leaves > square > flower > bolls of different cotton genotypes; maximum mortality was recorded when larvae fed on leaves of CEMB 33 followed by FH-118, FH-Lalazar, MNH-886 and FH-142, but minimum on FH-942 (non-Bt). The fourth and fifth instars were least susceptible to all tested cotton genotypes and maximum pupation, adult emergence and egg lying was observed. The percent mortality consistently decreased on instar wise basis (1st < 2nd < 3rd < 4th < 5th). The percent pupation, adult emergence and fecundity increased gradually and steadily for 4th and 5th instar larval bioassay. [ABSTRACT FROM AUTHOR]

The insect age plays a significant role in the intensity of competitive behaviours among the individuals. The courtship behaviour of brown planthopper (BPH) is followed by numbers of strides by both genders and influenced with age. In the present study, the age of male for 1-7 days and female 1-10 days was selected to observe the different parameters (male response time (MRT), male arrival time (MAT), male arresting time (MATt), number of times male extended genitalia (MEG), total pre-mating time (TPMT), mating duration (MD), female calling latency and female rejecting rate). In the results, a maximum MRT 13.14Ü.77 min was observed in DI. The BPH males approached to the female withjerky walking steps up and down with a minimum time of 0.24 i0.03 min in D3. After successful male arrival, male went for a maximum arresting time of 3.19i0.51 min by female in DI. Though, all the males extended their genitalia for successful copulation but DI male did not only take maximum time under female arresting but it also extended genitalia with maximum number of 5.80±0.37 times. Overall, a maximum pre-mating time of 16.70 ± 0.55 min and minimum 3.39 ± 0.17 were observed in DI and D5 males. The mating duration was lower in early ages (DI and D2) and became advanced / peaked in mid ages (D5 and D6) which later decreased again in D7. The physical behaviour of BPH females did not show any mating response during the first and second day of emerging. However, the lowest calling latency was observed in D9 (2.2 ± 0.3) and DIO (2.2 ± 0.3) and maximum in D3 (12.1 ± 1.5). The correlation coefficient also indicated strong with negative relationship (r= -0.92) between male age and total premating time and strong with positive relationship (r=0.95) between male age and mating percentage. [ABSTRACT FROM AUTHOR]

Potential role of triacontanol applied as a foliar treatment to ameliorate the adverse effects of salinity on hot pepper plants was evaluated. In this pot experiment, hot pepper plants under 75 mM NaCl stress environment were subjected to foliar application of 25, 50, and 75 µM triacontanol treatments; whereas, untreated plants were taken as control. Salt stress had a significant impact on morphological characteristics, photosynthetic pigments, gas exchange attributes, MDA content, antioxidants activities, electrolytes leakage, vitamin C, soluble protein, and proline contents. All triacontanol treatments significantly mitigated the adversative effects of salinity on hot pepper plants; however, foliar application triacontanol at 75 µM had considerably improved the growth of hot pepper plants in terms of plant height, shoot length, leaf area, plant fresh/dry biomasses by modulating above mentioned physio-biochemical traits. While, improvement in gas exchange properties, chlorophyll, carotenoid contents, increased proline contents coupled with higher SOD and CAT activities were observed in response to 75 µM triacontanol followed by 50 µM triacontanol treatment. MDA and H2O2 contents were decreased significantly in hot pepper plants sprayed with 75 µM triacontanol followed by 50 µM triacontanol foliar treatment. Meanwhile, root and shoot lengths were maximum in 50 µM triacontanol sprayed hot pepper plants along with enhanced APX activity on exposure to salt stress. In crux, exogenous application triacontanol treatments improved hot pepper performance under salinity, however,75 µM triacontanol treatment evidently was more effective in mitigating the lethal impact of saline stress via controlling the ROS generation and increment in antioxidant enzyme activities. [ABSTRACT FROM AUTHOR]

Stacking multiple genes into cotton crop to cop up multiple biotic stresses such as insects and weeds is a promising tool to save crop from losses. Transgenic cotton variety, VH-289, with double Bt and cp4EPSPS genes under the control of 35S promoter was used for the expression analyses and biosafety studies. The transgenic cotton plants were screened through PCR amplification of fragments, 1.7 kb for Cry1Ac, 582 bp for Cry2A and 250 bp for cp4EPSPS; which confirmed the presence of all genes transformed in transgenic cotton. The Cry1Ac + Cry2A and cp4EPSPS proteins were quantified through ELISA in transgenic cotton plants. The Glyphosate assay performed by spraying 1900 mL per acre of glyphosate Roundup further confirmed complete survival of transgenic cotton plants as compared to the non-transgenic cotton plants and all weeds. Similarly, insect infestation data determined that almost 99% insect mortality was observed in controlled field grown transgenic cotton plants as compared to the non-transgenic control plants. Evaluation of effect of temperature and soil nutrients availability on transgene expression in cotton plants was done at two different cotton growing regions, Multan and Lahore, Pakistan and results suggested that despite of higher temperature in Multan field, an increased level of Cry and cp4EPSPS proteins was recorded due to higher soil organic matter availability compared to Lahore field. Before commercialization of any transgenic variety its biosafety study is mandatory so, a 90 days biosafety study of the transgenic cotton plants with 40% transgenic cottonseeds in standard diet showed no harmful effect on wister rat model when studied for liver function, renal function and serum electrolyte. [ABSTRACT FROM AUTHOR]