Studies on Incidence of Jute Semilooper in Relation to Weather of Uttar Dinajpur, India (original) (raw)
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The mango mealy bug, Drosicha mangiferae population was studied during 2017-2018 at Malda District, West Bengal. The climatic parameters play a decisive role in determining the abundance and distribution of pest population. The observation on natural higher infestation of mealy bug was showed mango tree, besides this also on alternative host plants of guava and custard apple. The mango mealy bug first appeared on 7 SMW. Its population increased gradually and maximum population was noted at about 15 to 17 SMW in relation to the development of mango fruits in the orchard, afterwards its number decreases mostly from 18 SMW to 20 SMW. The present work was found correlation between mealy bug populations with climatic parameters. The mealy bug population was showed significantly positive correlation with minimum temperature and relative humidity gradient whereas, significant negative correlation with minimum relative humidity. The present works in near future will further developed an insect pest forecast model based on meteorological variables that help in the pest management programs.
Five different popular mango cultivars (Fazli, Guti, Lakhanbhog, Gopalbhog and Langra) of Malda, West Bengal, India were screened for the mango mealy bug (Drosicha mangiferae G.) population in panicle and trunk throughout the pest infestation period during 2018 and 2019. The average pest number at peak time (13 Standard Meteorological Week or SMW) of infestation indicated that maximum pest number of 132.57 and 28.05 was noted in the 30 cm branch of inflorescence and 10 cm 2 area of the trunk in Fazli cultivar. Whereas, minimum number of 20.27/ 30 cm branch of inflorescence and 6.36 in the same area of trunk was found in Langra. Study of various biological parameters of mealy bugs also indicated the the order of infestation of the five cultivars as Fazli>Guti>Lakhanbho g>Gopalbhog>Langra. Analysis of various biochemical parameters revealed that there was a significant positive correlation between pest density phagostimulants like sugar, protein, moisture and nitrogen. Significant negative correlation was observed between pest number and alkaloid, flavonoid, phenol, tannin, ascorbic acid as well as crude fibre suggesting their pivotal role in low pest incidence. By considering the adjusted R 2 in stepwise multiple regression model, it was noticed that tannin was the most significant factor (39.2 %) followed by nitrogen (15.5 %), flavonoid (11.4 %), phenol (7.7 %), ascorbic acid (6.9 %) and protein (6.2 %) to influence pest number. Factors like moisture (1.0 %), sugar (2.7 %), antioxidant (1.0 %) had minor contributions. Therefore, it can be concluded that a combination of factors influence pest density and a single factor is not adequate to affect the pest population. The study is helpful in understanding the host preference of mealy bug.
India is one of the world's largest jute producing country. Insect pests are one of the main constrains for underscoring jute production. To ensure and to stabilize production, farmers generally apply huge amount of insecticides of different newer brands. Toxic chemicals not only not only underscore the environmental health but also impart long, persistent and perennial effect on the farmer's health. Further, insect pest population evolved resistance to chemical pesticides due to producing large number of offspring with highest degree of mutation, variation, co-evolution and natural selection. Therefore emphasize on biological control in modern IPM practice to control insect pest population, by their natural enemy, predator and parasitoids is a time-needed programme. In biological control the 'agents' are targets on specific insect pest and control them without affecting other organisms and environment. The current review is an gross view on the processes of effectiv...
Current Journal of Applied Science and Technology
An experiment was conducted during pre-kharif season of 2016 and 2017 to determine the efficacy of relatively cheaper, safer horticultural mineral oil on yellow mite (Polyphagotarsonemus latus). The experiment was laid out in randomized block design with seven treatments [T1- mineral oil @ 3 ml/litre at 35 and 50 days after sowing, T2- mineral oil @ 6 ml/litre at 35 and 50 DAS, T3- mineral oil @ 9 ml/litre at 35 and 50 DAS, T4-Neem oil @ 3 ml/litre at 35 and 50 DAS, T5- mineral oil @ 3 ml/litre + neem oil @ 3 ml/litre at 35 and 50 DAS and T6- Control] replicated four times. Two scheduled spraying of each treatment was done on standing jute crop at 15 days interval. The effect of treatments was significant on post treatment mite population recorded after spray for both the cropping season. Among the treatments, T5 was found to be the most effective combination. The post treatment observation during 2016 and 2017 at 7 days after treatment indicated significantly less number of mites i...