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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #230459
Title: Vegetable Response to Herbicides Applied to Low-Density Polyethylene Mulch Prior to Transplant

Author
item CULPEPPER, A - UNIV OF GA
item GREY, T - UNIV OF GA
item Webster, Theodore

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2009
Publication Date: 7/1/2009
Citation: Culpepper, A.S., Grey, T.L., Webster, T.M. 2009. Vegetable response to herbicides applied to low-density polyethylene mulch prior to transplant. Weed Technology. 23:444-449.

Interpretive Summary: Vegetable production has been reliant on methyl bromide to control numerous weed species in over 100 crops. However, methyl bromide has been identified in the Montreal Protocol of 1991 as a chemical that contributes to the depletion of the Earth’s ozone layer. Therefore, the manufacture and importation of Methyl Bromide to developed countries followed a scheduled reduction plan, with elimination of use occurring 31 December 2004. A committee of the United Nations has granted critical use exemption for methyl bromide for selected crops use through 2009. Studies were initiated to evaluate the effect of herbicides applied to polyethylene mulch following irrigation or no-irrigation on vegetable transplants. Carfentrazone did not affect either crop in the irrigated or non-irrigated system. Irrigation readily removed glyphosate and paraquat from the LDPE mulch. Without irrigation, glyphosate and paraquat on the LDPE mulch reduced vegetable crop growth. Halosulfuron reduced squash growth and yield and tomato growth without irrigation. With irrigation, halosulfuron had no affect on tomato, but reduced squash growth. Flumioxazin killed both crops when the LDPE mulch was not irrigated and severely reduced growth with irrigation.

Technical Abstract: Few herbicides are available for weed control in vegetables. The elimination of methyl bromide increases the need for herbicides. An experiment was conducted to evaluate crop injury from herbicides applied to LDPE mulch prior to transplant. Irrigation (1 cm) or no irrigation following crop transplant was evaluated. Carfentrazone did not affect either crop in the irrigated or non-irrigated system. Irrigation readily removed glyphosate and paraquat from the LDPE mulch, as there was no adverse crop injury in these treatments. In the absence of irrigation, glyphosate and paraquat on the LDPE mulch reduced squash diameter and tomato heights 18 to 34%. Squash and tomato fruit biomass (yield) were reduced 25 to 33%, respectively. Halosulfuron reduced squash diameter and yield 71 to 74% and tomato heights and yields 16 to 37% in the absence of irrigation. With irrigation, halosulfuron had no affect on tomato, but reduced squash growth and yield 40 to 44%. Flumioxazin killed both crops when the LDPE mulch was not irrigated, and when irrigation was applied, reduced squash and tomato yield by 56% and 25%, respectively. These studies demonstrate crop safety of squash and tomato to carfentrazone applied to LDPE mulch, regardless of irrigation. When irrigation is applied prior to squash and tomato transplant, glyphosate and paraquat did not cause crop injury, while halosulfuron did not injure tomato when LDPE mulch received irrigation prior to transplant. Flumioxazin should not be applied to LDPE mulch prior to planting squash or tomato.