Comparison of the effectiveness of fumigant storin to control insect pests warehouse Lassioderma serricorne and Pholcus phalangioides

Insects warehouse pests contained in commodities, especially tobacco, can cause a decrease in the quantity and quality of commodity. The main pest insects found in tobacco storage warehouses are Lassioderma serricorne and Pholcus phalangioides. This study aims to analyze and compare the effectiveness of the use of fumigant storin to control insect pests L. serricorne and P. phalangioides. Methods used in this study include preparation of test insects, fumigation application, identification, calculation of mortality, and data analysis. The data were analyzed statistically using the One Way ANOVA test. The results showed that there was a significant difference in morphility between groups of test insects. Mortality is highest in the L. serricorne test insect group, which indicates that fumigant storin is very effective in controlling barn pest insects, especially L. serricorne. To control insect pests warehouses in the future, it is recommended to use biopesticides to be safer for food.

Beauveria bassiana: as a potential microbial biocontrol agent for tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae) in Dooars and Darjeeling, India

Background In the present study, the efficacy of two isolates of Beauveria bassiana namely, BKN20 and BKN1/14 was evaluated against the tea mosquito bug (TMB), Helopeltis theivora, Waterhouse (Hemiptera: Miridae) damaging harvestable shoots of tea plants in the Dooars and Darjeeling regions of West Bengal, India. Results Laboratory study revealed that, in both isolates, BKN20 was more pathogenic than BKN1/14, exhibiting 76% mortality of the test insect. The BKN20 isolate was formulated as an aqueous suspension (5%AS), and evaluated against TMB through micro-plot trials in tea plantations. The Micro-plot field study revealed a maximum of 72.19% reduction in the shoot damage due to TMB in plots sprayed with a 1000 ml/ha concentration of BKN20 5%AS containing 2 × 107 conidia/ml, as compared to the synthetic insecticide (Thiamethoxam 25%WG), where a 63.12% reduction in the shoots was recorded. Furthermore, different concentrations of the formulated BKN20 5%AS were evaluated against the test insect at 2 locations of tea gardens in the Dooars and Darjeeling regions. The results from both locations revealed that 1000 and 1200 ml/ha concentrations of BKN20 5%AS (each concentration containing 2 × 107 conidia/ml) significantly (p < 0.05) reduced the TMB population and they were more effective than Thiamethoxam 25%WG (120 g/ha). However, non-significant differences in crop yields were recorded. The formulation BKN20 5%AS was found to be non-pathogenic to non-target insects, i.e. natural enemies present in the tea ecosystem. BKN20 5%AS had no phytotoxic effect on the tea leaves, with acceptable organoleptic attributes. Conclusion The BKN20 isolate could be commercialized as an alternative microbial insecticide to reduce the load of chemical insecticides in the tea ecosystem.

Isolation, Purification and Elucidation of Stigmasterol and β-Sitosterol Glucosides from the Stems of Solenostemma argel Grown in Sudan and their Application as Insecticides

Two new compounds were isolated from the chloroform extract fraction of stems of Solenostemma argel, purified by column chromatography and elucidated by phytochemical and spectroscopic methods as Stigmasterol and β-sitosterol glucoside. Chloroform had the highest insecticide activity against the growth of the third larval instar of Tribolium castaneum used as a test insect, when it was compared with n-hexane, ethyl acetate, n-butanol and water extracts.

Comparison of the potential activities of viral and bacterial chitinases

Background Chitin, a long-chain polymer of N-acetylglucosamine, is a major structural component of the insect exoskeleton and the peritrophic membrane (PM). Chitinases are able to effectively break down glycosidic bonds of chitin polymer thus can be used in agriculture to control plant pathogen insects. These enzymes can be synthesized by higher plants, animals, protista, bacteria, and viruses. Results In this study, viral and bacterial chitinases were compared for their potential activity on a laboratory test insect. The genes encoding chitinases of Autographa californica nucleopolyhedrovirus (AcNPV) and Cydia pomonella granulovirus (CpGV) were amplified from genomic DNAs by PCR and cloned into the pET-28a (+) expression vector. The chitinase proteins of these 2 viruses (AcNPV-Chi, CpGV-Chi) and Serratia marcescens chitinase C (ChiC) protein which was previously cloned were overexpressed in Escherichia coli. Expressed proteins were purified and confirmed by western blot analysis as 50, 63, and 68 kDa for AcNPV, CpGV, and S. marcescens chitinases, respectively. Enzyme activities of the chitinases were confirmed. Chitinases were also compared to each other in silico. The insecticidal effects of these proteins were evaluated on Galleria mellonella L. larvae. Bioassays were performed on the 3rd instar larvae for each chitinase protein in triplicate. The results showed that although there were differences in enzymatic activities and domain organizations, all 3 microbial chitinases produced almost the same level of insecticidal activity on the test insect. LC50 and LT50 values were compatible with the mortality results. These results were a preanalysis for comparing the effects of microbial chitinases. Conclusion Potential activity experiments should be carried out on more insects to provide detailed information on the insecticidal effects of bacterial and viral chitinases.

Moringa water extract promising additive to prolong the activity of baculovirus under field-sunlight conditions in Egypt

Baculoviruses are considered as effective bio pesticides except of being not active under sunlight conditions. The aim of this study is to evaluate the capability of moringa extract to prolong virus activity under Egyptian field conditions especially that Moringa proved to be strong protective material under previous investigation under laboratory conditions the addition of moringa filters were tested on tomato plant foliage. Results are based on leaf bioassay using Spodoptera littoralis test insect and its nuclepolyhedrovirus (SpliNPV) as standard materials. The Original Activity Remaining (OAR) and Lethal Infectivity Time to 50% (LIT50) were estimated after exposure to natural sunlight. cacao and green tea were tested as comparative materials, which proved to be effective as virus protective agent in earlier investigations. The results showed that moringa additive at 10% sustained 50% of virus activity for 193.53 hours and 62.05 and 23.023 hours post application for cacao and green tea; respectively. While virus alone treatment lasts for only 17.551 hours. Moringa generally available, relatively cheap; it also has been tested and proved to be non-toxic, safe, and friendly to the environment. The obtained results showed the activity of moringa water extract in prolonging the virus activity under field application.

Insecticidal activity of cashew nut shell liquid against sucking pests of cowpea, Vigna unguiculata subsp. sesquipedalis (L.) Verdc.

Cashew nut shell liquid (CNSL), an important agro waste from cashew nut processing factories, was emulsified in water and assayed for insecticidal activity at concentrations ranging from 0.05 to 0.2 % against aphid, Aphis craccivora and pod bug, Riptortus pedestris infesting cowpea, Vigna unguiculata sesquipedalis under laboratory conditions by topical application. CNSL at various concentrations was found to have insecticidal properties against A. craccivora and R. pedestris wherein the speed of kill and efficacy varied with concentration and test insect. CNSL @ 0.1 % with mortality ranging from 95.83 to 100 per cent at 48 hours after treatment (HAT) was found effective against A. craccivora whereas a concentration of 0.2% was required against R. pedestris to achieve similar mortality (96.67 to 100 %) at 72 HAT. CNSL derived from two cashew nut processing methods (drum roasting and steam boiling) did not differ significantly in their insecticidal action. At concentrations of 0.1 and 0.2 %, mortality produced by CNSL was comparable to that of chemical insecticide, thiamethoxam 0.03% and significantly superior to the widely used botanical neem oil @ 2% against A. craccivora and R. pedestris respectively. R. pedestris that survived exposure to CNSL treatments exhibited developmental abnormalities and formation of nymphal adult intermediary indicating its possible insect growth regulatory effect.

Effect of Temperature and Relative Humidity on the Growth and Development of Acridid Grasshopper, Chrotogonus trachypterus Blanchard

Growth and development of acridid grasshopper, Chrotogonus trachypterus Blanchard was greatly influenced by different levels of temperature (20, 25, 30, 35 and 37oC) and relative humidity (40, 60 and 70%). A laboratory study was revealed that temperature between 30-35oC with 60% relative humidity is mostly suitable for life cycle of the test insect. Maximum oviposition period was 54.6±2.21 days at 25oC whereas, maximum hatching percent was recorded at 30oC (90.6±1.18). Average fecundity of a female increased with the increase in temperature up to 35oC (242.1±2.55) but decreased at 37oC. Developmental period of nymphs was longer at 20oC as 94.03±3.45 and 105.3±3.16 days for males and females whereas, nymphs quickly developed at 37oC within 50.3±0.55 and 60.2±2.44 days, respectively. Highest survivability was obtained at 25o and 30oC. Relative humidity ranged from 60-70% gave non-significant differences and found to be most suitable for insect growth. Study of interaction of ecological factors will be helpful in management strategy of the pest and future adaptation behavior and outbreak issues.

Impact of an Oomen feeding with a neonicotinoid on daily activity and colony development of honeybees assessed with an AI based monitoring device

Feeding experiments are standard tools in the pollinator risk assessment. The design (Oomen et al 1992) was developed to test insect growth regulators and herbicides. In recent years there was an update (Lückmann & Schmitzer 2015) on the outline in order to also focus on the advantage of different rates making a dose response design possible where exposure levels are known. Additionally, this design gives the possibility to test different rates for honey bee colonies foraging in the same landscape.The main objective of the experiment presented here was to determine the natural variability of foragers losses of hives fed with a sub-lethal neonicotinoid concentration compared to an untreated control. Other objectives were to see if the neurotoxic exposure results in any observable sub-lethal effects and to find out if losses can be correlated to hive development. This was assessed with traditional methods and a novel, visual monitoring device.

First report of Blister beetle, Mylabris pustulata Thunberg (Meloidae: Coleoptera) in maize fields from Sarson village of Almora District, Uttarakhand (India)

Orange banded blister beetle, Mylabris pustulata is an important species of Blister beetles and has been found to cause economic damage due to its polyphagous nature. In the present study, M. pustulata was found to be feeding on maize crop from Sarson village of Almora, Uttarakhand which is located on a ridge at the southern edge of the Kumaon Hills of the Himalaya range. This article brings into notice the damage by M. pustulata first time on maize from the specified area. The morphological features such as characteristic wing pattern, mouthparts, antennae etc. and feeding on sap or solid matter of floral or fruit in a similar manner as described in earlier texts revealed the similarity of test insect with M. pustulata.

Preliminary Tests Regarding Fumigant Effect of Volatile Oils Obtained from Medicinal Plants

The objective of this work was testing 4 volatile oils obtained from new varieties of medicinal plants (yellow basil; red basil; marigold; hyssop), over Beauveria brongniartii (BbgMm1a/09) entomopathogenic fungi and Sitophilus granarius, deposit insect. The results obtained showed that at different concentrations, red basil volatile oil showed the strongest inhibitory effect compared to the other tested oils (yellow basil, marigold and hyssop). Concerning the insecticidal action, the preliminary tests with the 4 volatile oils obtained from new varieties of medicinal plants had no effect on the test insect - Sitophilus granarius.