STUDIES ON MEALYBUG COMPLEX IN COTTON AND MANAGEMENT OF Phenacoccus solenopsis, TINSLEY
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Date
2019
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Acharya N G Ranga Agricultural University, Guntur
Abstract
The present investigation on “Studies on mealybug complex in cotton and management of Phenacoccus solenopsis, Tinsley” was carried out during 2018-19. Mealybugs were collected from three districts of Andhra Pradesh to identify their species complex and their natural enemies on cotton. Certain newer insecticides and indigenous materials against cotton mealybug, P. solenopsis were tested in the laboratory of Department of Entomology, Agricultural College, Bapatla.
A survey was conducted for the identification of species complex of mealybug on cotton in the Andhra Pradesh which included three districts viz., Guntur, Prakasam and Krishna covering two mandals in each district. In each mandal, three villages were selected for the collection of mealybug samples.
In Guntur and Prakasam districts, three mealybug species viz., P. solenopsis, Ferrisia virgata Cockerell, Paracoccus marginatus Williams and Granara de Willink were noticed on cotton. In addition to these three species, Pseudococcus jackbeardsleyi Gimple and Miller was also identified on cotton in Krishna district.
During the survey, different kinds of natural enemies were found in cotton ecosystem. A total of 13 species of natural enemies were identified. Out of these 13, nine were predators and four were parasitoids. Predators viz., Cheilomenes sexmaculata Fabricius, Brumoides suturalis Fabricius, Scymnus nubilus Mulsant, Coccinella transversalis Linnaeus, Angelies cardoni Weise, Telamonia dimidiate Simon, Hyllus semicupreus Simon, Neoscona theisi Simon, and a Neuropteran grub were identified. Four parasitoids belonging to the family encyrtidae, order Hymenoptera were recorded.
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Lethal concentrations of six insecticides viz., flonicamid, sulfoxaflor, thiamethoxam, buprofezin, dinotefuran and profenophos were determined against P. solenopsis crawlers and adults in a bioassay using potter’s spray tower. The LC50 and LC90 values of flonicamid, sulfoxaflor, thiamethoxam, buprofezin, dinotefuran and profenophos against P. solenopsis crawlers were 9.471 & 88.945 ppm, 1.323 & 10.653 ppm, 3.329 & 27.483 ppm, 25.699 & 276.757 ppm, 34.031 & 273.304 ppm and 14.537 & 111.480 ppm, respectively. The LC50 and LC90 values of flonicamid, sulfoxaflor, thiamethoxam, buprofezin, dinotefuran and profenophos against P. solenopsis adults were 37.037 & 531.014 ppm, 2.757 & 13.614 ppm, 15.154 & 119.606 ppm, 48.964 & 573.461 ppm, 42.792 & 295.520 ppm and 30. 992 & 287. 215 ppm, respectively.
Five indigenous materials viz., soap solution, starch, neem oil, NSKE and water were tested for their effect on P. solenopsis crawlers and adults by direct spray method of bioassay. The LC50 and LC90 values of soap solution, starch, neem oil and NSKE against P. solenopsis crawlers were 2.084 & 13.430 per cent, 3.130 & 16.836 per cent, 121.451 & 1493.539 ppm and 181.909 & 1587.322 ppm, respectively. The LC50 and LC90 values of soap solution, starch, neem oil and NSKE against P. solenopsis adults were 3.021 & 16.809 per cent, 5.924 & 23.755 per cent, 272.935 & 4262.431 ppm, 356.775 & 5114.560 ppm, respectively.
Combinations treatments of profenophos and indigenous material revealed that the treatment neem oil + profenophos was found to be the most effective against the P. solenopsis crawlers and adults as it had recorded high mean per cent mortality (92.86 per cent & 85.96 per cent). The treatment starch + profenophos was the least effective combination against the P. solenopsis crawlers and adults with mean per cent mortality of 87.72 per cent & 82.72 per cent, respectively.
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D5927
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