Relationship between Weather Parameters and Incidence of Gram Pod Borer, Helicoverpa armigera on Chickpea

Background: Chickpea, Cicer arietinum which is considered as a “King of pulses” get adversely affected by several biotic and abiotic stresses, out of which gram pod borer, Helicoverpa armigera (Hübner) is the major one. The damage caused by H. armigera starts from vegetative growth and continues till maturity of the crop. This pest is causes 25 to 70 per cent pod damage in chickpea but in favorable conditions pod damage goes upto 95 per cent. Methods: Present study was carried out during, rabi, 2014-15 and 2015-16 at Research Farm, College of Agriculture, Bikaner (Rajasthan). Correlation coefficient was worked out with weather parameters such as temperature (maximum and minimum), relative humidity (maximum and minimum), rainfall and sunshine hours. Multiple linear forms of regression model were also used to assess the effect of the weather parameters on the incidence of pod borer. Result: The studies revealed that peak larval population of gram pod borer was recorded in the second fortnight of February thereafter, population declined abruptly. The larval population of pod borer on chickpea occurred low at vegetative and flowering stages and high at pod formation as well as at grain developmental stages. The temperature (maximum and minimum) and sunshine hours had significant positive correlation with larval population during rabi, 2015-16. The maximum relative humidity showed significant negative correlation during rabi, 2015-16 whereas, minimum relative humidity showed significant negative correlation with larval population during both the seasons. The rainfall showed significant positive correlation during rabi, 2014-15.

Evaluation of IPM module against major insect pests of green gram, Vigna radiata (L.) Wilczek in lower Gangetic plains of West Bengal

An experiment was carried out to evaluate the efficacy of integrated management practices over farmers’ practices against insect pest complex of green gram (Vigna radiata L. Wilczek) during kharif season in the ‘A-B’ Block Farm of Bidhan Chandra Krishi Viswavidyalaya in 2019. The results revealed that the incidence of all of the insect pests viz. whitefly, pulse aphid, jassid, flower thrips, gram pod borer, spotted pod borer, blue butterfly, plant bug and pod bug was recorded comparatively less in Integrated Pest Management (IPM) plot as compared to farmers’ practices. The seed yield of green gram was also recorded a higher (1382.22 kg ha-1) in plots treated with integrated approaches as compared to farmer’s practices (476.94 kg ha-1). IPM module recorded maximum cost benefit ratio along with higher gross return and net profit as against farmers’ practices.

Prediction of Helicoverpa armigera (Hubner) larval population using weather based forewarning model in soybean

Weekly larval populations of pod borer, Helicoverpa armigera (Hubner) collected from 20 districts of Maharashtra under Crop Pest Surveillance and Advisory Project (CROPSAP) during 2010-2015 were analyzed to work out the effect of weather variables on the incidence of this insect on soybean. The appearance of larva was observed throughout the soybean growing season, and the peak incidence was observed during third week of August to first week of September (34-35 SMW). The correlation analysis of the data revealed that larval population was significantly and positively influenced by the minimum temperature and rainfall of current week as well as previous two weeks. For the development of forewarning model, data for the period from 2010 to 2013 were used as training dataset and two year (2014-2015) data as validation dataset. The mean model used for forewarning the incidence of pod borer larval population was developed by using step-wise multiple regression analysis in polynomial form. The results of mean model revealed that the significant variables affecting the pod borer larval population in soybean were maximum temperature (current and 1st lag week), and rainfall (current week) and the model explained 48.93% variation. The pre-disposing conditions for the incidence of larvae have been worked out as maximum temperature ranging from 26.1 to 31.47 ºC and rainfall ranging from 6.63 to 141.46 mm with low or medium rainfall in previous weeks followed by high in current week. The model was validated with 2014-15 independent dataset with predicted R2 (R2 ) value 28.13%. Two sample t-test showed no Pred significant difference between observed and predicted values (p = 0.3691 > 0.05).

The relationship of the morphological characteristics of some varieties of soybean on the attack itensity of the pod borer (Etiella zinckenella Treitschke) in two different cultivation techniques

Soybean is one of the secondary crops that are often planted by the farmer. One of the most common pests that attack soybeans is the pod borer (Ettiela zinkenella T). One of the ways to control pests is by using varieties that are resistant to pod borer attacks. The research objectives were to examine the relationship between the morphological characteristics of soybean pods and to determine the handling with the lowest attack intensity. The experiment used a split plot design with two factors and three replications. The research material was the seeds of five soybean varieties, namely Detap-1, Dega-1, Anjasmoro, Biosoy, and Dena-1 which were planted in 2 different lands. The highter the trichome pods, the lower the attack intensity with a value of -68.321, if X=0 then Y=64.081 and for the R2 value in the relationship, which is 0.2532. The longer the pod trichomes, the higher the attack intensity with a value of 0.0683, if X=0 then Y=18.208 and for the R2 value in the relationship, which is 0.0007. The thicker the skin of the pod, the lower the attack intensity with a value of -68.321, if X=0 then Y=64.081 and for the R2 value in the relationship, which is 0.2532. The harder the skin texture of the pods, the lower the attack intensity with a value of -0.0308, if X=0 then Y=36.614 and for the R2 value in that relationship, 0.2355. The recommended technology treatment with Anjasmoro variety had the lowest attack intensity compared to other treatments.