1. Abstract Results & Discussion
Weed control is critical to maximize watermelon production and to produce quality fruit. S- S-metachlor applied overtop
metolachlor (Dual Magnum) could fit into watermelon herbicide program as it is an proved to be harmful to
effective tool for managing problematic weeds such as pigweed and select grasses. A watermelon seedlings
study was conducted in Crisp County to evaluate watermelon response to S-metolachlor. regardless of application
Watermelons were transplanted into bareground or mulch (flat bed) production systems timing, rates of S-metolachlor
and treated with S-metolachlor applied topically at 12 or 24 ounces per acre. Both rates of S-
applied, or production system
metolachlor were applied immediately after transplanting as well as 3, 6, 9, and 12 days after.
Treatments were replicated four times and a non-treated control in both production systems was included (baregound or mulch) and
for comparison. Topical applications of S-metolachlor at 12 and 24 ounces per acre injured melons as should not be considered as
much as 80%. Injury included un-acceptable vine stunting and delayed growth regardless of application an herbicide option for
timing, rate of herbicide, or production system (bareground/mulch) when compared to the non-treated watermelon producers.
control. Additional efforts will investigate the potential for using S-metolachlor as a row middle Negative seedling effects
application which may improve control of problematic weeds without harming the crop. included abnormal growth,
stunting (fig. 2), and terminal
Situation lesions (fig. 3) of plants when compared to non treated control plots (fig. 4).
Weed control is critical for watermelon production Yield data was
and quality. Watermelon producers currently have several variable among
residual pre-emergence herbicides for the control of grasses treatments however
and broadleaf weeds. However with the loss of naptalam considering
(Alanap), producers could benefit from an additional consistent early
topically applied herbicide that provides residual control season vine
for select grasses and pigweeds (fig. 1) Previous research has damage, S-
shown that preplant applications of S-metolachlor can stunt watermelon vines and metolachlor is not
delay maturity. However, no research has been conducted evaluating watermelon considered as a
response to topical applications of S-metolachlor in either a bareground or mulched feasible option in a
production system. Timing of application, rates of S-metolachlor applied, and watermelon
production system could impact the severity of crop injury and should be herbicide program when applied topically to the watermelon. However
investigated to determine if S-metolachlor could be an option for watermelons. further research is needed
to determine the potential
Methods & Materials for S-metolachlor as a row
A trial was established in Crisp County to evaluate effects of in row, topical middle herbicide option for
applications of S-metolachlor in watermelons. Mardi Gras watermelon were watermelon producers.
transplanted on 29 April according to UGA recommendations with a spacing of 2’ in
row and 15’ between row. Site soil type was Tifton loamy sand. Treatments Assisting in Project
Doug Collins
included S-metolachlor applied at 12 or 24 ounces per acre in 15 gallons of water
Lee County Extension ANR Agent.
per acre over-the-top of watermelon seedlings planted into bareground or mulch Roxie Price
(36”, 8 mil, black). Treatments were made during the day of planting as well as 3, 6, Dougherty County Extension EFNEP Agent.
9 and 12 days after planting. Treatments were replicated 4 times and a non-treated
control within each production system was included for comparison. Vine ratings
were conducted 25 May and 28 June. Individual plots were harvested 7, 14, and 21
July.