(F77) PEANUT: Arachis hypogaea L., 'VA 98R' EFFECTS OF FOLIAR-APPLIED INSECTICIDES ON THRIPS INJURY AND YIELD OF VIRGINIA-TYPE PEANUT, 2001 D. A. Herbert, Jr. Virginia Tech Tidewater Agricultural Research and Extension Center 6321 Holland Road Suffolk, VA 23437 Phone: (757) 657-6450, ext. 122 Fax: (757) 657-6450 E-mail: firstname.lastname@example.org Tobacco thrips (TT): Frankliniella fusca (Hinds) Selected foliar-applied insecticides were evaluated against TT injury and for effects on yield of Virginia- type peanut. 'VA 98R' peanut was planted 7 May at the Virginia Tech Tidewater Agricultural Research and Extension Center, Suffolk, VA, using 36-inch row spacing. Foliar sprays were applied on 24 May and again on 4 Jun with a CO pressurized backpack sprayer as a broadcast (BC) at 14.3 gpa and 18 psi through 8002VS nozzles spaced 18 inches apart on the spray boom. An RCB experimental design was used with four replicates; plots were four rows by 40 ft. TT injury was evaluated based on a 0 to 10 scale where, 0 = no thrips induced plant injury, 1 = 10% injured leaves, 2 = 20% injured leaves, 3 = 30% injured leaves, 4 = 40% injured leaves, 5 = 50% injured leaves + 5% terminal buds injured, 6 = 50% injured leaves + 25% terminal buds injured, 7 = 50% injured leaves + 50% terminal buds injured, 8 = 50% injured leaves + 75% terminal buds injured, 9 = 50% injured leaves + 90% terminal buds injured, and 10 = dead plants. Yield was determined from digging, drying, and combining peanuts from the two center rows of each plot. Data were analyzed using ANOVA and LSD procedures. Thrips injury reached a peak of 6.3 in the untreated control plots on 8 Jun and remained high (6.0) through 20 Jun. All treatments provided significant control compared with the untreated control on all sampling dates, except Vydate C-LV at the lowest rate tested (0.25 lb(AI)/acre) on 31 May and 14 Jun. For each product tested, there was a general decrease in injury as rates increased, and some decreases were significant. Temik 15 G (IF), which was included as an insecticide standard, conferred the lowest injury levels on all dates, and significantly lower than all other treatments on 31 May and 8 Jun. Only Karate Z at the highest rate tested (0.03 lb(AI)/acre) had injury levels equal to Temik 15 G on 14 Jun. By 20 Jun, Baythroid 2 EC (both rates tested), F 0570 0.8 EC at the highest rate (0.017 lb(AI)/acre), and Orthene 97 (both rates tested) also had injury levels equal to that of Temik 15 G. The highest yield was conferred by Temik 15 G (3,946 lb/acre), but not significantly different compared with those conferred by both Karate Z or Orthene 97 treatments, or the highest rates of F 05070 0.8 EC or Baythroid 2 EC. Only the Vydate C-LV treatments resulted in yields not significantly different from the untreated control.
Arthropod Management Tests – Oxford University Press
Published: Jan 1, 2002