Chemical and Cultural Control of the Sunflower Moth In Texas12

Abstract

Tests were conducted to determine the effectiveness of 14 insecticides for control of Homoeosoma electellum (Hulst). Tests at McGregor, Tex., showed that VCS 506 ( O -(4-bromo-2,5-dichlorophenyl) O -methyl phenylphos. phonothioate), endosulfan, diazinon, GS-13005 ( O, O- dimethyl phosphorodithioate S -ester with 4-(mercapto-methyl)-2-methoxy-∆2-1,3,4-thiadiazolin-5-one), methyl parathion, and naled reduced the larval infestation following 2 and 3 spray applications, Plots treated twice with endosulfan, diazinon. GS-13005, and methyl parathion had significantly increased yields. Following 3 applications, all treated plots yielded significantly more seed per acre than the untreated plots. Test at College Station, Tex., showed that 2 conventional low volume applications of Azodrin® (3-hydroxy- N -methyl- cis- crotonamide dimethyl phosphate), carbaryl, malathion, azinphosmethyl, mevinphos, Dursban ( O, O -diethyl O -3.5,6 trichloro-2-pyridyl phosphorothioate), toxaphene, and parathion reduced the number of larvae and increased yields. Larval reductions and increased yields were also obtained after 2 ultra low volume applications of methyl parathion, azinphosmethyl. and malathion. Dates of planting studies showed that sunflower moth larvae infestations were lowest in plots planted April 15 or later. Low insect levels did not always result in high seed yields, in most cases because of inadequate moisture Oviposition studies indicated that the greatest sunflower moth oviposition occurred on the 3rd day after sunflower heads opened. Also, approximately 75,0% of sunflower moth oviposition was completed by the end of the 6th day after the heads opened.