Field Performance of LA 850082, LA 870210, LA HG660, and DP 51 with Selected Insecticide Use Strategies

M. E. Barfield, D. S. Calhoun, B. R. Leonard, and S. H. Moore


The tobacco budworm (TBW), Heliothis virescens (F.), and bollworm (BW), Helicoverpa zea (Boddie), are two major insect pests of cotton, Gossypium hirsutum L. Recent history has documented the development of insecticide resistance within the TBW/BW complex. This study was conducted to evaluate the efficacy of host plant resistance in combination with selected insecticide use strategies for TBW/BW control. Three TBW/BW resistant genotypes, La 850082, La 870210 and La HG660, and 'Deltapine 51' (DP 51) were treated with lambda-cyhalothrin (Karate 1EC) at either 0.016 lb [AI]/acre (Karate LR) or 0.032 lb [AI]/acre (Karate HR) or remained untreated at the Dean Lee Research Station (DL), Alexandria, La and Northeast Research Station (NE), Winnsboro, La. in 1992 and 1993. La 850082 expresses the frego bract, nectariless and smoothleaf characters and probably additional unknown factors for resistance. La 870210 and La HG660 are recognized as having the high gossypol gland density character for resistance. Plots were arranged in a split-plot treatment arrangement within a randomized complete block design with insecticide treatments representing main plots and genotypes were sub-plots. Treatments were replicated five times in each trial. Karate treatments were applied to all plots when larvae were present in 5% of the terminals in Karate HR treated plots of DP 51. Infestation and damage ratings were collected by examining 25 plant terminals and 25 fruiting structures per plot on several sample dates. Yields were estimated by harvesting the two, center rows of each plot with a two-row spindle-type cotton picker. Generally, plots of DP 51 had a significantly higher percentage of TBW/BW damaged fruit than other genotypes. Usually, untreated plots had a significantly higher percentage of TBW/BW damaged fruit than plots receiving either rate of Karate treatment. Usually, La 870210 produced significantly more lint than other genotypes at DL. At NE, La 870210 and DP 51 were the highest yielding genotypes. In 1992 at DL and 1993 at NE, untreated plots produced significantly less lint than plots receiving either rate of Karate treatment. A significant genotype by insecticide treatment interaction for lint yield was observed in 1992 at DL where plots of DP 51 responded the most to increasing rates of Karate treatments. The results of our data suggests that a statistically equal level of TBW/BW suppression can be achieved by using resistant cotton genotypes and reduced rates of Karate treatment with no significant reduction in yield.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pg. 713
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998