Pushpinder J. Rup

Role of Eisenia fetida in rapid recycling of nutrients from bio sludge of beverage industry.

Beverage industry bio sludge proved to be toxic when given alone to earthworms even after stabilization for 15 days, therefore, it was mixed in various proportions with cattle dung. Best suitable mixture for highest survival, maximum growth and highest population buildup of Eisenia fetida was determined by observing mortality, growth rate, rate of cocoon production, population buildup and time taken for decomposition of waste. Minimum mortality and maximum population buildup were observed in 50:50 mixture of bio sludge and cattle dung. Nitrogen, phosphorous, sodium and pH increased in all the feed mixtures, while electrical conductivity, organic carbon and potassium declined in all the samples in comparison to traditional compost (without worms). Degradation of 50:50 mixture could be achieved in 75 days when worms were inoculated at 25 g/kg feed mixture. But the best-quality product was obtained after 105-110 days with 7.5 g worms/kg feed mixture.

Cocomposting with and without Eisenia fetida for conversion of toxic paper mill sludge to a soil conditioner.

Present study was envisaged for fast bioremediation of toxic paper mill sludge into a soil ameliorating agent. Although a rich source of organic carbon this sludge cannot be directly applied in fields and is recycled very slowly in landfills as it is deficient in other nutrients. Therefore it was mixed with cattle dung in various proportions and subjected to aerobic cocomposting (without worms) and vermicocomposting (with Eisenia fetida). It was observed that mixing cattle dung with the sludge improved physico-chemical characteristics (with transition metals in the permissible range for manures) of the products of both the processes and enhanced its acceptability for worms. Higher decline in organic carbon and higher content of nitrogen and phosphorous along with lower electrical conductivity and higher pH of the products of vermicomposting indicated that E. fetida helped in fast conversion of toxic paper mill sludge into a soil conditioner in 100days.

Acute, sublethal and combination effects of azadirachtin and Bacillus thuringiensis toxins on Helicoverpa armigera (Lepidoptera: Noctuidae) larvae.

The efficacy of neem (1500 ppm azadirachtin (AI)), Delfin WG, a biological insecticide based on selected strain of Bacillus thuringiensis Berliner (Bt) subspecies kurstaki, and Cry1Ac protein, either individually or in combination, were examined against first to fourth instar Helicoverpa armigera (Hübner) larvae. Using an oral administration method, various growth inhibitory concentrations (EC) and lethal concentrations (LC) were determined for each bioagent. Combinations of sublethal concentrations of Bt spray formulation with azadirachtin at EC50 or EC95 levels not only enhanced the toxicity, but also reduced the duration of action when used in a mixture. The LC20 and LC50 values for Cry1Ac toxin were 0.06 and 0.22 microg ml-1, respectively. Bt-azadirachtin combinations of LC50+EC20 and LC50+EC50 result in 100% mortality. The mortality also was significant in LC20+EC20 and LC20+EC50 mixtures. These studies imply that the combined action is not synergistic but complimentary, with azadirachtin particularly facilitating the action of Bt. The Bt spray-azadirachtin combination is more economical than combinations that involve isolating the toxic protein, as the Bt spray formulations can be combined in a spray mixture with neem. These combinations may be useful for controlling bollworm populations that have acquired resistance to Bt as they may not survive the effect of mixture. Azadirachtin may be useful as a means of reducing the endotoxin concentrations in a mixture, to promote increased economic savings and further reduce the probability of resistance development to either insect control agent.

Toxicity of some essential oil constituents and their binary mixtures against Chilo partellus (Lepidoptera: Pyralidae)

Allelochemicals from essential oil-bearing plants have been categorized as green pesticides because they are biodegradable and predominantly non-toxic to vertebrates. With an aim to reduce the use of synthetic insecticides, they represent one of the most promising approaches for eco-chemical control of insects. Eight compounds were evaluated via topical application against third instar Chilo partellus Swinhoe larvae. Thymol was the most active (lethal dose (LD)50 = 189.7 μg/larva) and methyl eugenol the least (LD50 = 1069.4 μg/larva). The compounds were also tested at sublethal levels, i.e. LD10 and LD30, and there was approximately 15–43% of reduction in growth, which was transitory, and some recovery was observed 6 days post-treatment. Compounds were also used as binary mixtures and tested for synergy, using toxicity and feeding inhibition parameters. The data showed that thymol and α-terpineol synergized the effects of both linalool and 1,8-cineole, but linalool with 1,8-cineole exhibited only an additive effect against C. partellus. Although there is no specific generalization that could be drawn relating to efficacy of binary mixtures, the present findings resulted in several complex mixtures that couid be developed and tested as leads for effective control of C. partellus.

Evaluation of regulatory influence of four plant growth regulators on the reproductive potential and longevity of melon fruit fly (Bactrocera cucurbitae)

The topical treatment given to freshly emerged (0–1-day-old) male and female adults ofBactrocera cucurbitae (Coquillett), a serious pest of cucurbit crops in tropical countries, with 25, 125, 625 and 3125 ppm concentrations of gibberellic acid (GA3), indole-3-acetic acid (IAA), kinetin and coumarin showed a significant adverse influence on the reproductive potential of this fruit fly. The assessment for reproductive potential was made on the basis of reduction in fecundity and fertility of laid eggs and measured as sterility in females and shortening of the longevity,i.e. ovipositional phase. The strongest influence was with kinetin, followed closely by coumarin, then GA3 and lastly with IAA treatments. It was concluded that although these compounds demonstrate their activities differently in plants and might be following a different mode of action in insects, they ultimately influence the reproductive potential of this insect.

Mating and its attendant behaviour in Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Abstract An analysis of about 100 encounters between males and females of Callosobruchus maculatus , permitted identification of the main units of mating behaviour. The premating phase of males could be divided into 8 units, followed by mating and post-mating phases. Duration of mating was 3.17±0.37 (1.4–6.1) min. Frequency of mating was highest on the 1st day of emergence and the urge to mate decreased with age. The diel cycle also influenced mating frequency. Males often attempted to mate soon after a successful mating, whereas females did not.

Exploration for anti-insect properties of lectin from seeds of soybean (Glycine max) usingBactrocera cucurbitae as a model

Lectin fromGlycine max L. was extracted and purified by affinity chromatography using asialofetuin-linked porous amino-activated silica beads. The concentration-dependent effect of lectin was studied on freshly laid eggs (0–8 h old) of the melon flyBactrocera cucurbitae (Coquillett); lectin failed to influence egg hatching. However, treating second instar larvae (64–72 h old) with increasing concentrations of lectin significantly reduced the development period, number of pupae and number of emergingB. cucurbitae, and was negatively correlated with the increase in the lectin concentration. The LC50 value, 54µg ml−1, was calculated on the basis of adult emergence. Treatment of the larvae (64–72 h old) with the LC50 concentration resulted in a decrease in pupal weight. The activity of three hydrolase enzymes (esterases, acid and alkaline phosphatases), one oxidoreductase (catalase) and one group transfer enzyme (glutathione S-transferase) was assayed in second instar larvae at the LC50 concentration of lectin after exposure for 24, 48 and 72 h. The activity of esterases increased significantly (P<0.01) at the three exposure intervals, whereas the activities of the three other hydrolyses and the transferases were significantly suppressed (P<0.01).

Oviposition and feeding behavior of the maize borer, Chilo partellus , in response to eight essential oil allelochemicals

Eight essential oil compounds were evaluated against the maize borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), to determine their influence on oviposition and feeding behavior. Thymol was the most active compound against C. partellus when evaluated as an oviposition deterrent (ODI50 = 1.36 mg ml−1), an ovicide (LC50 = 2.06 mg ml−1), or a feeding deterrent (FI50 = 141.8 μg cm−2) in laboratory experiments. The results corroborated with greenhouse experiments, in which egg laying on maize plants was inhibited significantly when the treatment was 15 times the concentration used in the laboratory experiments. However, there was neither any correlation between oviposition deterrence and feeding inhibition, nor between oviposition deterrence and ovicidal action. Apparently, toxicity per se or ovicidal action does not play any role in choice of oviposition in C. partellus. This was more obvious when the efficacy of compounds was compared in greenhouse experiments where ODI values and number of eggs laid on the treated leaves did not differ significantly in choice and no‐choice situations. Apparently, toxicity plays an important role in predicting host plant choice, but behavioral response in terms of oviposition preference is independent of toxic action, particularly for non‐host toxins. Thus, the same compounds affecting oviposition behavior on the one hand and having ovicidal or feeding deterrent properties on the other could be useful in field situations in any area‐wide integrated pest management model.

Influence of Four Plant Growth Regulators on Development of the Melon Fruit Fly, Bactrocera Cucurbitae (Coquillett)

Experiments were conducted to assess the effect of four plant growth regulators (PGRs), namely coumarin, kinetin, gibberellic acid (GA3) and indole-3-acetic acid (IAA), on the development of the melon fruit fly, Bactrocera Cucurbitae (Coquillett) (Diptera: Tephritidae). All four compounds exerted growth- and development-inhibitory effects on the fly. Coumarin was most potent, followed by kinetin, GA3 and IAA. The first and second instars of the fly were more sensitive than the third instar. Treatment with the PGRs also prolonged the fly’s developmental period, reduced percentage emergence and increased percentage of abnormal flies emerging. At the higher concentrations tested (125, 625 and 3125 μg/ml) coumarin, kinetin and GA3 caused 100% mortality in first instars.RésuméDes expérimentations ont été conduites pour évaluer les effets de 4 régulateurs de croissance de plante (RCP), la coumarine, la kinétine, l’acide gibbérélique (AG) et l’acide indole-3-acétique (AIA), sur le développement de la mouche du melon, Bactrocera Cucurbitae (Coquillett) (Diptera: Tephritidae). Les 4 composés ont des effets inhibiteurs sur la croissance et le développement de la mouche. La coumarine est peu active, suivie de la kinétine, de l’AG et de l’AIA. Les premiers et seconds stades de la mouche sont plus sensibles que le troisième stade. Le traitement avec les RCP prolonge également la période de développement de la mouche, réduit le pourcentage d’émergence et augmente le pourcentage de mouches adultes anormales. Aux plus fortes concentrations utilisées (125, 625 et 3125 μg/ml) la coumarine, la kinétine et TAG sont responsables de 100% de mortalité au premier stade.

Effect of hydroprene on Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Abstract The effect of the insect growth regulator, hydroprene, was observed on Callosobruchus maculatus (F.). Hydroprene was applied topically to the last 2–3 sternites of unmated males and females with a micropipette. No significant decrease in fecundity was observed even with the highest dose of 0.75 μg of hydroprene, whereas the fertility of the eggs laid by treated females was affected on the first day of the oviposition period even with the lowest dose of 0.1 μg, and the effect was diluted with time. Male fertility was also affected. The emerged F 1 adults showed morphological abnormalities and the developmental period was prolonged.