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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #167295
Title: COVER CROP, RYE RESIDUE AND IN-FURROW TREATMENT EFFECTS ON THRIPS

Author
item Olson, Dawn
item Davis, Richard
item PHATAK, S - UNIVERSITY OF GEORGIA

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/22/2006
Publication Date: 5/15/2006
Citation: Olson, D.M., Davis, R.F., Brown, S.L., Roberts, P., Phatak, S.C. 2006. Cover crop, rye residue and in-furrow treatment effects on thrips. Journal of Applied Entomology. 130(5):302-308. DOI:10.1111/j.1439-0418.2006.01066.x.

Interpretive Summary: Thrips feeding damage on cotton, Gossypium hirsutum L., seedlings can have many deleterious effects on cotton, and yield losses suffered in many cases has resulted in most growers using an in-furrow treatment of aldicarb for pest control. However, the lethal and sublethal effects of aldicarb on a diversity of non target species suggest that an alternative thrips control option would be desirable. In this study, Thrips, thrips damage, plant stand, seed-cotton yield and root-knot nematodes were compared in plots with in-furrow treatments of aldicarb, phorate, and diammonium phosphate (DAP) fertilizer under two tillage and winter cover regimes to determine the potential of the fertilizer and cover crop combination to increase seedling vigor for plant protection from thrips. Thrips numbers were significantly higher in the conventional fields with winter weeds than the clover fields regardless of in-furrow treatment in 2002, but in 2003 were significantly higher in the conventional field only for the control and fertilizer treatments. Plant damage was higher in the conventional than the cover crop field except in the aldicarb treatments. Within the cover crop fields, plant damage was highest in the control and similar in the fertilizer, aldicarb and phorate treamtments. Plant stand and yield was highest in the conventional field but did not differ with respect to the in-furrow treatments. Root-knot nematode numbers were low and not related to field-type or in-furrow treatment. These results suggest that conservation tillage with a winter clover cover and an in-furrow treatment with Dap may be a viable alternative thrips control method in dry-land cotton in fields without significant nematode populations.

Technical Abstract: We investigated the potential for an in-furrow fertilizer and leguminous winter cover for their combined potential as an alternative to aldicarb use for thrips control in cotton. Crimson clover was planted in the fall of 2002 and 2003 and strip-killed prior to planting. Cotton in 16 40 by 20m plots representing the in-furrow treatments replicated 4 times. The treatments were : 1) control = cotton seed only, 2) diamonium phosphate (dap), (NPK, 10-34-0), at 0.946L/A on treated area of a 25.5cm band, 3) aldicarb (15G) and 4) phorate (20G) each at 3.5 lb/A. For 3 weeks each year 10 cotton seedlings per plot was assayed for thrips and thrips damage. Damage was: percent leaf damage and if the plant had tip damage or not. For the former, a classification of 1 = 0-20% leaf damage, 2 = 21-40%, 3 = 41-60% 4 = 61-80%, and 5 = 81-100%. Tip damage was noted and a 1 added to the leaf damage for an estimate of total plant damage. Nematodes were sampled from soil on 3 dates each year. Cotton stand and yield were estimated on one date in 2002. Anova and chi-square analysis was used to test the influence of replication, field and treatment on thrips, stand and yield and plant leaf and plant tip damage from thrips (SAS Institute, 1987). Thrips numbers and thrips damage were reduced in the clover cover field compared to the conventional field, and within the clover field plant damage did not differ with respect to the in-furrow treatments. Nematodes were low and did not increase in numbers throughout the study. Our results suggest a possible alternative to aldicarb use for thrips control in cotton fields without high plant parasitic nematode populations.