353 



693. . 1972. Resistance levels and results of laboratory insecticide tests 

 for controlling bollworms, tobacco budworms and boll weevils. Tex. Agric. 

 Exp. Stn. Prog. Rep. PR-3089, pp. 7A-85. 

 Laboratory studies were conducted to evaluate the toxicities of certain in- 

 secticides to the bollworm, Heliothis zea (Boddie) , tobacco budworm, Heliothis 

 viresceus (F.) and boll weevil, Anthonomus grandis Boheman. Resistance to 

 methyl parathion and monocrotophos by tobacco budworms for 2 areas of Texas 

 was about the same in 1971 as in 1970. The 1971 LDcU value for methyl parathion 

 for tobacco budworms from the Brazos Valley near College Station was 0.11 (milli- 

 grams per gram; the LDr^ value for budwoims from Weslaco was 0.27 mg/g. In- 

 creased resistance to monocrotophos by tobacco budworms from College Station 

 was observed. The LDj. values established for methyl parathion and monocroto- 

 phos for the bollworm in 1971 did not change significantly from the LDr„ values 

 established during the previous 7 years. This indicated that bollworms have 

 not developed detectable resistance to the organophosphorus compounds. Extremely 

 large dosages of most insecticides did not produce adequate mortality of tobacco 

 budworms on treated plants. The organophosphorus and carbamate insecticides 

 gave high mortalities of bollworms at moderate test dosages in caged plant 

 tests. The chlorinated hydrocarbon compounds were generally ineffective 

 against bollworms. All insecticides tested a'^ainst boll weevils produced 



694. , and Adkisson, P. L. 1968. Laboratory tests of effectiveness of 



certain insecticidal sprays for controlling the bollworm, budworm and 

 boll weevil. Tex. Agric. Exp. Stn. Misc. Publ. MP-876, 7 pp. 

 Toxicities of several insecticides to bollworms, Heliothis zea (Bod.), tobacco 

 budworms, Heliothis virescens (F.), and boll weevils, Anthonomus grandis Boh. 

 were determined in laboratory studies during 1967. Methyl parathion and Azodrin 

 were the most effective indivicfual materials tested against the bollworm. Also, 



,.^ t^.tJ£:;^^t'^i^J.'^»^-t.^^-tl*'ijm.i^J^'.^>*^^^^^rfit-^S-^~r.%^-t. '-"--^ -i*" 



