Specific identification, biology and symptoms of whitefly species infesting sunflower in South India

Whitefly species related to sunflower was identified as Bemisia tabaci (Gennadius). Further the identified whitefly species was confirmed to be indigenous B. tabaci on molecular basis by using B-biotype specific SCARs and biological silver leaf assay on sensitive pumpkin (cv Big variety). None of the whitefly samples could positive for the presence of B biotype. The results of the study on the pest life cycle under the laboratory conditions showed that, B. tabaci passed through four nymphal instars before the adult stage. The mean duration values of these stages were 5.6, 4.2, 4.4 and 5.6 days respectively. The total duration of the life cycle of B. tabaci ranged from 23- 42 days at the temperature of 29±2°C with a mean of 34.5. The damage to sunflower crop caused by the whitefly species is discussed with a special emphasis on its ability to transmit leaf curl viral disease

Temperature Effects on the Development of Life Stages of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on Maize

The effect of temperature on the development of different life stages of Spodoptera frugiperda on maize was assessed at the Centre for Agro Climatic Studies, University of Agricultural Sciences, Raichur at five different constant temperatures viz., 18, 22, 26, 30, and 32°C with a constant relative humidity 65 ± 5% for all the temperatures under growth chambers conditions. Over the temperature studied, the duration of different life stages decreased with a rise in temperature from 18 to 32°C. Where, the duration of the egg stage reduced from 6.00 days (1°C) to 2.00 days (32°C); for the larva from 31.50 to 10.10 days and for the pupae from 30.86 to 6.0 days. The temperature ranges of 26 to 30°C were found to be favourable for growth and development whereas the temperature extremities of 18 and 32°C were not favourable for the growth and development of fall armyworm; at 18°C there was no eclosion and at 32°C there was eclosion of adults but mortality occurred within an hour. The linear regression studies revealed that lower developmental threshold temperatures of 11.50, 11.49, 13.90, and 20.13 and corresponding thermal constants of 43, 236, 149, and 494 degree days were recorded for the incubation period, larval period, pupal period and total life cycle respectively in order. The present study revealed that the upper threshold of 32°C and a lower threshold of 18° C were detrimental to the development of fall armyworm life stages. These estimated thermal thresholds and degree days might be used to predict the fall armyworm activity in the field for devising strategies to manage fall armyworms effectively

Determination of imidacloprid in brinjal and okra fruits, decontamination and its dietary risk assessment

Brinjal and okra are being sprayed withdifferent formulations of imidacloprid which leads to significant deposition of residues on fruits. Here in this study, we validated a method that could detect the traces of imidacloprid residues in a short run time using LC-MS/MS. LOD of 0.001 and LOQ of 0.003 μg/g for brinjal and in compliance with the MRL (0.2 mg/kg). The recovery at different spiking levels recorded 89.67 to 115.55 with an RSDr range of 3.02 and 5.22%. For okra, 0.0025 and 0.008 μg/g were observed as LOD and LOQ, respectively. Recovery was obtained between 88.69 and 93.74%. Precision in terms of repeatability (RSDr) and reproducibility (RSDwR) was found satisfactory in both matrices. Two applications of imidacloprid 17.8% SL in both vegetables showed faster dissipation initially and persisted up to 15–25 days. Decontamination with 2% salt solution followed by boiling for 15min. removed 96.43 and 73.66% of imidacloprid residues from brinjal and okra, respectively. Risk assessment was found to be less than one (HI < 1) for brinjal and okra matrix and can be safely consumed