Incorporation of lyophilized leaves and pods into artificial diet to assess antibiosis component of resistance to pod borer in pigeonpea

Helicoverpa armigera, is the most damaging insect pest of grain legumes including pigeonpea in the semi-arid tropics, and host plant resistance is an important component for the management of this pest. Because of the variation in insect density over space and time, it is difficult to assess the contribution of different components of resistance to this insect under field conditions. Therefore, we standardized a bioassay involving incorporation of lyophilized leaves or pods into the artificial diet to assess antibiosis component of resistance to H. armigera. Antibiosis was assessed in terms of larval mortality, larval and pupal weights, adult emergence, and duration of development on fresh leaves, flowers and pods, and through incorporation of lyophilized leaves and pods of different pigeonpea genotypes into the artificial diet. Incorporation of 10 g of lyophilized leaf or pod powder into the artificial diet (300 ml) of diet resulted in maximum differences in survival and development of H. armigera larvae on the resistant (ICPL 332) and susceptible (ICPL 87) genotypes. Reduced larval and pupal weights, and prolongation of larval and pupal development periods were observed in insects reared on intact leaves or pods of ICPL 332, ICPL 84060, ICP 7035, ICPL 88039 and T 21. Similar effects were also observed in larvae reared on artificial diet impregnated with lyophilized leaves or pods of ICPL 332, ICPL 84060, ICP 7035, ICPL 187-1, ICPL 88039, and ICP 7203-1. Larval and pupal periods, pupal weight, and pupation and adult emergence were positively correlated between the insects reared on fresh leaves or pods, and on artificial diets impregnated with lyophilized leaves or pods. However, there was no correspondence in terms of larval weight and mortality between the fresh plant parts and diet impregnation assay. Incorporation of lyophilized leaves or pods of pigeonpea into artificial diet for assessing the antibiosis component of resistance to H. armigera has been discussed

Stability of resistance to pod borer, Helicoverpa armigera in pigeonpea

Because of increasing difficulties in controlling the damage by the pod borer, Helicoverpa armigera in pigeonpea with synthetic insecticides, it is important to identify genotypes with resistance to this pest for use in integrated pest management. Therefore, we evaluated a set of 12 diverse genotypes for resistance to H. armigera for two years over four plantings under natural infestation. There were significant differences among the genotypes in numbers of eggs and larvae, percentage pod damage, visual damage rating, and grain yield. The genotypes ICPL 187-1, ICP 7203-1, ICPL 98008, T 21, ICP 7035, and ICPL 332 exhibited moderate levels of resistance to H. armigera across planting dates, although there were a few exceptions. ICPL 187-1, ICP 7203-1, ICPL 84060, ICPL 87119, and ICPL 332 also showed better grain yield potential than the susceptible checks, ICPL 87 and ICPL 87091. All the genotypes were stable in their reaction to pod borer damage based on visual damage rating (except ICPL 87119 and ICPL 84060), but unstable for percent pod damage. Grain yield of most of the genotypes under H. armigera infestation was also unstable, except that of ICPL 87119, ICP 7035, and ICPL 332. Principal component analysis placed the test genotypes into different groups, and there is a possibility of increasing the levels and diversifying the basis of resistance to pod borer, H. armigera

Integrated Pest Management (IPM) for Reducing Pesticide Residues in Crops and Natural Resources

Investigation on the pesticide residues during 2006–2009 in various crops and natural resources (soil and water) in the study village (Kothapally, Telangana State (TS)) indicated the presence of a wide range of insecticidal residues. Pooled data of the 80 food crop and cotton samples, two rice grain samples (3 %) showed beta endosulfan residues, and two (3 %) soil samples showed alpha and beta endosulfan residues. In vegetables of the 75 tomato samples, 26 (35 %) were found contaminated with residues of which 4 % had residues above MRLs. Among the 80 brinjal samples, 46 (56 %) had residues, of these 4 % samples had residues above MRLs. Only 13 soil samples from vegetable fields were found contaminated. The frequency of contamination in brinjal fields was high and none of the pulses and cotton samples revealed any pesticide contamination. IPM fields showed substantial reduction sprays which in-turn reflected in lower residues. Initial studies on water analysis indicated the presence of residues in all water sources with higher in bore wells compared to open wells, however, by 2009 the water bodies reflected no residues above the detectable level

Not Available

Not AvailableA study was conducted to estimate certain organochlorine (OC) pesticides (DDT, HCH and cyclodiene compounds) and heavy metals (lead and cadmium) residues in muscle and organs of pigs collected from Hyderabad city. The residues of organochlorine pesticides and heavy metals were found in majority of the analysed muscle and organs samples of pigs. The contamination pattern of OC pesticides in tissues of pigs were in the descending order of p,p’DDT- para para dichloro diphenyl trichlore ethane (0.213 ppm), p,p’DDE- para para dichlorodiphenyl dichlore ethane (0.132 ppm), p,p’DDD- para para dichloro diphenyl dichloroethylene (0.058 ppm), α endosulfan (0.037 ppm), β HCH - hexachloro cyclo hexane (0.028 ppm), δ HCH (0.022 ppm), endosulfan sulfate (0.018 ppm), α HCH (0.017 ppm), β endosulfan (0.016 ppm), aldrin (0.016 ppm) and γ HCH (0.014 ppm). However, the levels of contamination were quite low and well below the maximum residue level. Among tissues, muscle showed the highest concentration for p,p’DDD; p,p’DDT; β HCH; aldrin; α endosulfan; β endosulfan and endosulfan sulfate, whereas liver showed the highest mean concentration for γ HCH and δ HCH. The concentrations of p,p’DDE and α HCH were highest in kidneys. The heavy metals residues were found in all the analysed meat and organs samples. In most of the cases, the levels of contamination were low and below the maximum residue level except in case of lead, where 40.9% samples exceeded the maximum permitted limit. Among tissues, kidney showed highest concentrations for both lead and cadmium.Not Availabl