Radiation Biology of Fall Armyworm, Spodoptera Frugiperda (j.e. Smith)



Department of Entomology, S.V. Agricultural College, ANGRAU, Tirupati – 517 502.


Maize (Zea mays L.) is 3rd most important cereal crop next to rice and wheat sharing about 2% of world’s maize production. Maize is called as “Queen of cereals” due to its productivity potential over other cereal crops. Fall armyworm is a serious pest of maize known to feed on more than 350 plant species belonging to cereals, millets, cotton and vegetables. The use of insecticides as a sole tool in the management of insect pests has potential drawbacks such as the development of insecticide resistance, persistence of pesticide residues on crop produce, outbreak of secondary insect pests and pest resurgence. Determination of the optimum dose of gamma radiation for male sterilization without compromising the quality of adults in terms of adult emergence, adult longevity and survival of sterile males is crucial in the successful application of SIT. Exposure of mature pupae of Spodoptera frugiperda to gamma radiation (Co-60 source) at doses ranging from 25 to 100 Gy had least negative impacts on adult emergence and deformation. Further increase in radiation doses ranged between 125-200 Gy significantly decreased the adult emergence with increase in percentage of deformation. The longevity of adult moths from the pupae irradiated at 25, 50 and 75 Gy was 8.67, 8.33 and 7.5 days respectively and on par with control. The longevity of irradiated males at 100 and 125 Gy was 6.00 and 5.00 days, respectively. Whereas males irradiated at 150, 175 and 200 Gy lived up to 4.33, 3.67 and 2.50 days respectively. Males exposed to gamma radiation showed an inverse relationship between the percentage of survival and radiation doses. At 25 and 50 Gy, survival rates were 72.33% and 67.50%, respectively and were significantly different from the control (76.20%). No significant difference was found at 75Gy and 100 Gy with survival rates of 61% and 59%, respectively. Percentage of survival of male moths from the pupae irradiated at 125, 150, 175 and 200 Gy significantly reduced to 47.00%, 41.00%, 26.80% and 21.50% respectively.


KEYWORDS: Fall armyworm, Gamma radiation, Quality parameters, Adult longevity.

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