Evaluation of parasitic potential of Anisopteromalus calandrae (Howard) against Callosobruchus maculatus (F.), Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) in grains treated with diatomaceous

The herein reported study was conducted to evaluate the parasitic potential of Anisopteromalus calandrae (Howard) against larvae of Callosobruchus maculatus (F.), Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) while, adult pests on the food medium treated with two formulations of diatomaceous earth (DE); Marine (Celite) and fresh water (Perma Guard) as grain protectants. The DE was applied at three dose rates i.e., 200, 400 and 600 ppm, at 25°C temperature and 65% relative humidity. Mortality and emergence of adults of tested insects and parasitoid were observed after 14 and 28 days of exposure respectivly. The highest mortality of C. maculatus was 43.37% against higher dose of Perma Guard (600 ppm) while the maximum mortality of S. oryzae was recorded 39.56% on application of Celite (600 ppm). The maximum mortality of A. calandrae parasitoid was observed 66.86% in S. oryzae infested grains treated with higher dose of Perma Guard (600 ppm), while 63.81% mortality of parasitoid was observed in S. oryzae infested grains at higher dose of Celite DE (600 ppm). The Perma Guard effectively controls population of tested insect’s mortality than the Celite. The highest emergence of C maculatus observed was 62.44% at lower dose of 200 ppm of Perma Guard DE while the highest emergence recorded on application of Celite was 60.66% from C. maculatus. The highest emergence of A. calandrae was 65.65% from S. oryzae at lower dose of 200 ppm of Perma Guard DE while the highest emergence of parasitoid recorded on application of Celite was found 60.66% at lower dose of 200 ppm from C maculatus. The emergence of tested insects and parasitoid increased with the decrease in dose rate of DE in most of the tested combinations. Higher dose (600 ppm) of both DE (Celite and Perma Guard) used in experiment showed mortality of tested insects and parasitoid activity of Anisopteromalus calandrae and furthermore release of A. calandrae on host insects would be adversely affected by use of diatomaceous earth product on stored grains. The experiments were carried out in laboratory of Grain Research, Training and Storage Management cell, Department of Entomology, University of Agriculture Faisalabad.

Frass produced by the primary pest Rhyzopertha dominica supports the population growth of the secondary stored product pests Oryzaephilus surinamensis, Tribolium castaneum, and T. confusum

Primary pests such as Rhyzoperta dominica may increase the contents of dockage, dust, and frass in grain mass. Although it has been suggested that frass can affect the population growth of stored product pests and ecological interactions among primary and secondary pests in stored grain, this has not been validated experimentally. Therefore, this work experimentally tested the hypothesis that R. dominica wheat frass may support population increases in secondary pests such as Tribolium confusum, T. castaneum, and Oryzaephilus surinamensis for the first time. The effect of frass on secondary pest performance was compared with the effects of various physical qualities of wheat grain (i.e., intact grain kernels, grain fragments, flour, grain + frass) and an artificially enriched control diet (milled wheat kernels, oat flakes, and yeast). The results showed that the clean intact grain kernels did not support the population growth of any tested species, and the nutrient-rich control diet provided the best support. Frass was a significantly better food medium for O. surinamensis and T. castaneum than flour or cracked grain, while T. confusum performed equally well on flour and frass. Our results showed that in terms of food quality and suitability for the tested species, frass occupied an intermediate position between the optimized breeding diet and simple uniform cereal diets such as cracked grain or flour. The results suggest that (i) the wheat frass of primary pest R. dominica is a riskier food source for the development of the tested secondary pests than intact or cracked wheat grain or flour; (ii) frass has the potential to positively influence interspecific interactions between R. dominica and the tested secondary pests; and (iii) wheat grain should be cleaned if increases in R. dominica populations and/or accumulated frass are detected.

Diversity in external morphology, sex comb and developmental stages of three Drosophila species of melanogaster group

Samples of Drosophila species were collected from some selected sites (viz., Dohar Upazila of Dhaka Division, Hironpoint of the Sundarbans, Satchori of Sylhet Division) of Bangladesh and these were cultured in the laboratory to study developmental stages, external morphological traits and sex comb. They were identified as D. melanogaster, D. ananassae and D. bipectinata. The sex comb teeth number and arrangement were distinct for all three species. D. melanogaster had one row of 10 - 11 teeth in the sex comb. D. ananassae had eight rows of teeth in the sex comb possessing 32 - 33 teeth in total. D. bipectinata had 2 - 3 rows of teeth in the sex comb and total teeth number varied from 11 to 15. Among three species, sex comb teeth number of D. bipectinata varied most. Eleven different patterns (n=20) in sex comb were observed in D. bipectinata indicating significant diversity within species. Variation in pupation sites among three species was also observed in the laboratory condition. D. bipectinata pupated on the food medium, whereas other two species pupated on the vial wall. Thus, diversity among these three species of Drosophila was documented which could be utilized as bioindicator in future. Dhaka Univ. J. Biol. Sci. 28(2): 167-176, 2019 (July)

Trichopria drosophilae (Diapriidae) and Leptopilina heterotoma (Figitidae), native parasitoids of Drosophila suzukii, confirmed in Slovenia

The Spotted-wing drosophila (SWD), <em>Drosophila suzukii</em> (Matsumura, 1931) (Diptera, Drosophilidae) was recorded for the first time in Slovenia in autumn 2010. Shortly thereafter, it turned out to be one of the most important insect pests of soft and stone fruit in Slovenia and elsewhere. Within the expert work in the field of plant protection, more precisely within task inventarisation of beneficial organisms for biological control, the presence of indigenous <em>D. suzukii</em> parasitoids was investigated in 2018. Sentinel traps baited with <em>D. suzukii</em> larvae and pupae in banana slices enriched with artificial food medium for drosophilids were used for inventorying <em>D. suzukii</em> parasitoids in raspberries. The pupal parasitoid<em> Trichopria drosophilae </em>(Perkins, 1910)<em> </em>(Hymenoptera: Diapriidae) and the larval parasitoid <em>Leptopilina heterotoma </em>(Thompson, 1862)<em> </em>(Hymenoptera: Figitidae)<em> </em>were recorded parasitizing <em>D. suzukii</em>for the first time in Slovenia in August 2018 in Central Slovenia (Ljubljana).<p> </p><p> </p><p> </p>

EFFECT OF NICOTINE ON SEXUAL BEHAVIOUR OF MUTANT STRAIN (CURLED) OF DROSOPHILLA MELANOGASTER

In the present study, an attempt was made to study the effect of plant extract on Sexual behaviour of Mutant Strain (Curled) of Drosophila melanogaster. The LC50 has been estimated with 1% of the food media. The virgin females and males were isolated and fed with normal food media for three days. Then sub-lethal concentrations of 0.625 μl / 100 ml food, 1.2 μl /100 ml food, 2.5μl /100 / food of nicotine were mixed in food medium and allowed in flies to feed for two days. Then appropriate combination of untreated / treated males and females were introduced into the mating chamber. Courtship latency, mating latency and copulation duration were studied. After observation of the behaviour, mated flies were allowed to produce progeny. The sexual behaviour of bachelor male and virgin female obtained in the progeny was also studied. The pooled data were analyzed by student t-test and the result indicates p-value significant at 0.05 levels. The courtship latency was affected by in treatment but it is neither dose dependent nor sex dependent.

Migration Detection of Residual Solvents from Composite Packaging Film to Food by GC-Ms

An analytical method was developed to measure the migration of residual solvent from composite packaging film to food medium. By using gas chromatography / mass spectrometry, migration levels of toluene and ethyl acetate, the main residual solvents in composite packaging film were measured in food so that the migration characteristic of toluene and ethyl acetate in different simulations was studied. The results show that all the linear correlation coefficient were greater than 0.999 and the detection limit was lower than 0.005μg/ml. This method is of high sensitivity, accurate analysis of quantity and can meet the practical demands.