Co-Operation Impact Between Gamma Radiation and Spraying Droplets Distribution for Bioinsecticides Controlling Boll Pests on Cotton Plants in Egypt

Abstract

Field experiments were carried out of about 8 karats planted with (Giza 86) cotton variety during seasons 2018 and 2019 on 21st July and 5th, 20th August in a field located at Qaha Research Station, Plant Protection Research Institute, Qalyoubia governorate. The selected area was split into 7 plots and the control plot. Two spraying machines were used Pneumatic motor sprayer (Cifarilli) (20 L./Fed.) and Hand-held Hydraulic sprayer (Matabi) (56 L./fed.) for application enhancement. Seven compounds related to different insecticide groups were used; one of them (B. thuringiensis)was exposed to gamma radiation doses of 160, 320 & 640 Gy (gray) =for potentiating purpose. The treatments were Bacillus thuringiensis (Kurstaki), B. thuringiensis +160 Gy, B. thuringiensis +320 Gy, B. thuringiensis +640 Gy, azadirachtin, B. thuringiensis +azadirachtin and diflubenzuron. The treatments mentioned were evaluated against three pests of cotton bolls that were pink bollworm, Pectinophora gossypiella (Saund); spiny bollworm, Earias insulana (Boisd.) and Cottonseed bug, Oxycarenus hyalinipennis (Costa) population and infestation reduction percentages. B. thuringiensis +640 Gy and diflubenzuron were considered the best treatments that caused reduction percentages in population and infestations against three pests used, followed by B. thuringiensis +320 Gy, B. thuringiensis +160 Gy and B. thuringiensis + azadirachtin, azadirachtin and then B. thuringiensis. In addition, the compounds used to enhance the most cotton crop parameters acts in seed numbers, lint and seed weights during the two cotton seasons 2018 & 2019. So, gamma radiation (160, 320 & 640 Gy) could potentiate B. thuringiensis to become the most effective compound on mentioned three pests and cotton crop parameters compared with the same compounds without exposing to gamma radiation; also, knapsack motor sprayer contribute to success the pest control comparing with Hand-held Hydraulic sprayer (Matabi) (56 L./fed.) that was the least efficient according to homogeneity of droplet spectrum. It could be recommended to use these Bio-Insecticides with Low Volume spraying equipment with not less than (20 L/Fed.). A satisfactory coverage was obtained on cotton plants. The spectrum of droplets ranging between 122-185 mm (VMD). With a sufficient number ranging from 33-253 N/cm². The rate of performance of Pneumatic motor sprayer (Cifarilli) (20 L./Fed.) was 12 Fed./day. It was the best equipment, but the lowest rate of performance was Hand-held Hydraulic sprayer (Matabi) (56 L./fed.) since it could spray only 3.45 Fed./day. Data showed that bio-insecticides may be recommended in integrated pest management because of their safety on animals, man and environment. Also, Low Volume spraying reducing the time lost in the process filling the machines with the spray solution and saving the lost spray on the ground.