Morphological and Biochemical Bases of Resistance of Some Groundnut Germplasms against Tobacco Caterpillar, Spodoptera litura (Fabricius) and Leaf Miner, Aproaerema modicella (Deventer)

A screening experiment of forty germplasm lines was conducted at College Farm, College of Agriculture, Rajendranagar, Hyderabad in rabi, 2019-20 and was laid in Randomized block design (RBD) having two replicates. Three germplasm lines viz., ICGV 16679 (13.71% leaf damage), ICGV 07222 (14.00% leaf damage) and ICGV 93468 (14.25% leaf damage) showed greater resistance than the resistant check, ICGV 86031 (15.04% leaf damage) against tobacco caterpillar and with respect to resistance against leaf miner, no germplasm line was found to be superior than the resistant check, ICGV 86031 (7.82% leaf damage). However, the germplasm line, ICGV 02266 (8.35% leaf damage) was next best to the resistant check. The various morphological and biochemical characters were recorded and correlated with insect pest damage and incidence to know their role in imparting resistance/susceptibility. Resistance to various insect pests in germplasm lines was due to significantly higher trichome density on leaf lamina, higher phenol and tannin content.

Thermal energy requirement for tobacco caterpillar Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) development on artificial diet

Development and survival of tobacco caterpillar Spodoptera litura larvae and pupae were studied at each of seven constant temperatures, 15±1, 18±1, 21±1, 24±1, 27±1, 30±1 and 33±1°C, in incubators. Oviposition, in-cubation, larval and pupal periods were recorded at each of the temperatures. The survival from 1st instar to adult emergence ranged between a maximum of 60% at 24°C and 30% at each of 18°C and 33°C. Developmental duration of different larval instars and pupae declined with an increase in temperature from 15 to 33°C. The optimum temperature for larval and pupal survival in S .litura on artificial diet was observed to be 24°C. On the other hand, optimum temperature range for oviposition was observed to be 27-33°C.The relationship between temperature (T) and development rate (r) was established using linear regression to estimate the thermal constant (K) and development threshold (T0).Thermal constant for 1st to 6th larval instars were computed as 76.9, 90.9, 125, 83.3, 62.5, 90.9 and 200 degree days (DD), respectively, with corresponding development thresholds as 12.8, 11.7, 9.8, 10.3, 10, 10.9 and 13.2oC. Single developmental threshold for larval stage was computed as 13°C.These thermal constants and development thresholds can be used in developing mechanistic population simulation model, which in turn will facilitate the assessment of climate change impact on the pest.

Population dynamics of stem fly and defoliator pests of soybean and their natural enemies in relation to weather parameters

The field experiment was carried out at Polasa Farm, Regional agricultural research station Jagtial during the Kharif, 2014-15 and 2015-16. Study about pre dominant lepidopteran insect –pests in soybean crop noticed that the tobacco cut worm, (Spodptera exigua Hubner), green semi looper(Crysodexis acuta Walker), and tobacco caterpillar (Spodoptera litura Fab) along with stemfly, (Melanagromyza obtusa Zehnter) as non lepidopteran pest were noticed at various growth stages of cropgrowth. The peak activity of stem fly (37.84%) was observed during 37th standard week per meter row) for the year 2014 and for the year 2015 to a maximum infestation of 35.70 per cent during 30th std.week. The peak activity of caterpillar pests i.e., S. litura (7.6 larvae per meter row) for the year 2014 was observed during 34th std.week and for the year 2015 (12.4 per meter row during 36th std.week and C. acuta (0.7 larvae per meter row) during 36th std. week for the year 2014 and for the year 2015 (2.20 larvae/mrl on 37th std week. S. exigua (1.6 larvae per meter row) for both the years 2014 and 2015 was observed during 32th std.week Among the natural enemies, one predators namely, spiders (Oxyopes sp. was observed to prey on the insect pests.The biocontrol agent’s one species, lynx spider, Oxyopes sp. population recorded on the crop during Kharif , 2014 ranged from 0.15 to 0.40 /mrl and 0.15 to 0.60/ mrl during Kharif, 2015.

Diversity of Arthropods and Population Dynamics of Diamondback Moth Visiting Organically Cultivated Cabbage

The biodiversity of insects visiting cabbage and population dynamics of diamondback moth was studies on Golden acre variety of cabbage. The experiment was conducted at experimental plot of Ramakrishna Mission Vivekananda Educational and Research Institute, Morabadi, Ranchi, during October to January, 2018-19. During the experiment, Bihar hairy caterpillar, Diamondback moth, Cabbage aphid, Cabbage maggot, Cabbage butterfly, Tobacco caterpillar, Ladybird beetle, Rice bug, Cricket and Spider were noticed. The population of diamondback moth was positively correlated with maximum, minimum, average temperature and maximum relative humidity and negatively correlated with minimum RH, wind speed; rainfall. The highest larval population of was recorded during 1st week of January (1st Standard Meteorological Week, SMW).

Cluster Frontline Demonstration: An Effective Technology Dissemination Approach for Enhancing Productivity and Profitability of Black Gram (Vigna mungo)

Background: Pulses are versatile crops that are better for nutritional security and soil health. Black gram (Vigna mungo L.) is most important pulse crop, grown throughout the country. The productivity of Black gram is low in Patan district because non-adoption of scientific technologies by the farmers like use of poor quality seeds, water stress at critical stages, imbalance use of plant nutrient, infestation of weeds and incidence of pest especially mosaic, blight, tobacco caterpillar and sucking pest.Methods: The present study was carried out by the Krishi Vigyan Kendra, Samoda- Ganwada, Taluka- Siddhpur, District - Patan (Gujarat) during Kharif season. Krishi Vigyan Kendra, Patan (Gujarat) conducted 225 demonstrations in farmer’s field of Patan district during three years i.e., from Kharif, 2017-18, Kharif, 2018-19 and Kharif, 2019-20 on integrated crop management (ICM). Front line demonstrations on black gram were organized in nine cluster in different taluka of Patan District. The demonstrated technology is improved variety (GU-1), Optimum seed rate (20 Kg/Ha), Seed treatment by fungicide and insecticide, Soil inoculation by NPK-liquid consortia Bio fertilizer @ 5 Lit/ Ha, RDF as per STV, water management at critical stages, IWM and application of IPM module for the management of insect (Specially on Tobacco Caterpillar and pod borer) and Yellow Mosaic diseases.Result: Reduce the pest infestation under demonstrated technology of black gram resulted enhance the productivity is 24.51 per cent in demonstrated plot over farmers practice. The net return from demonstrated technology is ranged from Rs 28530 per ha in 2018-19 to Rs 36830 per ha in 2019-20 whereas in farmers practice, it was ranges from Rs 20700 in 2017-18 to Rs 30200 in 2019-20. The benefit: cost ratio of black gram cultivation under demonstrated technology was 3.10 whereas in farmer’s practices, it was 2.77.

Evaluation of Pathogenicity of Symbiotic Bacteria of Entomopathogenic Nematodes against the Larvae of Tobacco Caterpillar, Spodoptera litura F. (Lepidoptera; Noctuidae)

The tobacco caterpillar, Spodoptera litura is a polyphagous pest with attacking almost 290 host plants species globally causing a wide range of yield losses to the agricultural crops. In this investigation symbiotic bacteria of entomopathogenic nematodes were evaluated for their insecticidal activity against larvae of S. litura under lab conditions. The intact cell suspension and cell-free extract were screened for their bacterial pathogenicity and the results showed mortality of larvae after 24h of post treatment. The percent mortality treated with intact cell suspension was significantly higher in larvae treated with EPB3 strain with 90% which was on par with the reference strain Bacillus thuringiensis after 72h of post treatment. There is no significant difference among the larval mortality treated with cell-free supernatant. The virulence test was carried out to find out the LD50 and LT50 against the larvae and the results showed that EPB3 and B. thuringiensis required 104 CFU for 50% lethality of larvae with a media lethal time of 24h and 22h, respectively when treated with cell suspension. In case of larvae treated with cell-free extract, LD50 value with 105-106 CFU with a median lethal time ranging from 33-45h. The results showed that the isolates EPB3 (Xenorhabdus nematophilus) is comparatively more virulent than other Photorhabdus isolates against the test insect S. litura. Further these symbiotic bacteria can be screened for their biocontrol efficiency under greenhouse and field conditions and can be developed as potential biopesticides against the insect pests.

Spodoptera litura (taro caterpillar).

The tobacco caterpillar, S. litura, is one of the most important insect pests of agricultural crops in the Asian tropics. It is widely distributed throughout tropical and temperate Asia, Australasia and the Pacific Islands (Feakin, 1973; Kranz et al., 1977). Records of S. litura having limited distribution in (or being eradicated from) Germany, Russian Federation, Russian Far East, the UK and Réunion may in fact refer to S. littoralis. Both S. litura and S. littoralis are totally polyphagous (Brown and Dewhurst, 1975; Holloway, 1989) and therefore have huge potential to invade new areas and/or to adapt to new climatic and/or ecological situations. The Spodoptera group consists of closely related species with similar ecology that are difficult to identify to species level.