ISHS Acta Horticulturae 487: VI International Symposium on Processing Tomato & Workshop on Irrigation & Fertigation of Processing Tomato
RECENT RESEARCH DEVELOPMENT IN TOMATO WEED MANAGEMENT |
| Authors: | R.J. Mullen, J. Caprile, T.C. Viss, R.W. Whiteley, C.J. Rivara |
| Abstract:
During the 1997 processing tomato season, a number of weed management trials were conducted in the Northern San Joaquin Valley of California, covering both preemergence and postemergence treatments for control of Solanu and other weed species. Herbicides evaluated for preemergence weed control included metam-sodium at 54 kg/ha, rimsulfuron (0.018 to 0.035 kg/ha), dimethenamid (0.42 to 0.84 kg/ha), napropamide (2.24 kg/ha), metolachlor (2.80 kg/ha), pebulate (6.72 kg/ha), trifluralin (0.56 kg/ha) and FOE-5043 (1.01 kg/ha). Materials tested for postemergence weed management were rimsulfuron at 0.018 to 0.035 kg/ha and metribuzin at 0.14 and 0.28 kg/ha. All trials had four replications using a randomized complete block design. With exception of metam-sodium, all others herbicides were applied with CO2 backpack sprayer in a spray volume of 280 1/ha. In a combination preemergence/postemergence study near Brentwood, CA, one-half of the trial area was treated with metham-sodium, as a subsurface layered treatment, 12 days before field seeding and the remaining trial area was not. After field planting, other preemergence herbicides were applied to the surface of the tomato beds and sprinkler incorporated with 1.9 cm of water. Postemergence applications of rimsulfuron plus crop oil concentrate (COC) and metribuzin alone were made over some of the metam-sodium treatments three and one half weeks later. Excellent control of black nightshade (Solanumnigrum L.) and hairy nightshade (Solanum sarrachoides Sentner) occured with preemergence combinations of metam-sodium plus rimsulfuron, rimsulfuron plus dimethenamid, rimsulfuron plus napropamide, and rimsulfuron used alone Postemergence applications of rimsulfuron plus COC were also very effective. None of the treatments were effective on seedling field bindweed (Convolvulus arvensis L.). The combination preemergence treatments of rimsulfuron plus dimethenamid caused a temporary reduction in crop growth. All treatments gave greater yields than the untreated control, led by the preemergence treatment of rimsulfuron, alone at 0.026 kg/ha. giving 143.5 MT/ha. A pre-transplant mechanically incorporated weed control experiment near Tracy, CA evaluated six herbicides and/or combination treatments for control of black and hairy nigthshade, common fiddleneck (Amsinckia intermedia Fisch, and Mey.) and shepherdspurse (Capsella bursa-pastoris L.). After the treatments were applied to the bare tomato soil incorporation was accomplished using a Performer tiller pulled by a Challenger tractor, a new innovation. The field was transplanted the following day with a furrow irrigation applied 24 hours later. Best control of all weed species present occured with rimsulfuron at 0.035 kg/ha). All treatments showed excellent crop safety and outyielded the uncreated control, led by rimsulfuron at 117.7 MT/ha. The same herbicides were evaluated in a layby incorporated trial on a direct seeded tomato field, northwest of Tracy, CA, when the crop was 15 to 20 cm tall. Applications were made as directed sprays and then soil incorporated 7.6 cm deep with a conventional power driven rotary tiller. Best control of hairy nightshade, barnvardgrass (Echinochloa crus-galli L.). and smooth crabgrass (Digitaria ischaeman Schreb Ex Muhl) was achieved by rimsulfuron at 0.035 kg/ha, followed closely be dimethenamid at 0.84 kg/ha. Both of these treatments also produced the highest yields (99.2 MT/ha and 95.2 MT/ha, respectively). All treatments exhibited excellent crop safety and outyielded the untreated control. A postemergence weed control trial south of Banta, CA, evaluated rates of rimsulfuron with four different adjuvants (X-77, crop oil concentrate (COC), SCOIL, and SILWET) and metribuzin, alone and in combination with rimsulfuron plus COC. Applications were made over the tomatoes and black nightshade when they were at the cotyledon to first true leaf stage of growth. Weed control was excellent with all treatments except metribuzin alone. Minor growth suppression increased with all adjuvants as the rate of rimsulfuron increased from 0.018 to 0.035 kg/ha; SILWET showed more injury than the other adjuvants. At harvest there was no significant difference in yield with any of the treatments, including the untreated control. | |
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