Influence of Tillage, Cover Crop, and Preemergence Herbicides on Weed Control and Pumpkin Yield

Abstract

ABSTRACT Many Midwestern and Eastern U.S. jack-o-lantern pumpkin (Cucurbita pepo L.) growers are interested in using no-tillage production practices. However, improved weed management practices must be developed before no-tillage will be readily adopted for pumpkin production. A field study was conducted to determine effects of tillage, winter rye (Secale cereale L.), and preemergence herbicides on weed control and pumpkin yield. Grass and broadleaf weed control was greater in no-tillage compared to conventional tillage, and cover crop use in a no-tillage system further improved the level of weed control. Early- and late-season control of giant foxtail (Setaria faberi Herrm.), common cocklebur (Xanthium strumarium L.), redroot pigweed (Amaranthus retroflexus L.), and common waterhemp (A. rudis Sauer) were highly correlated (0.48 ≥ r ≤ 0.86, P ≤ 0.01) with pumpkin yield and fruit size. Although applying clomazone+ethalfluralin to winter rye residues improved broadleaf weed control compared with no herbicide, the level of control for all broadleaf species was unacceptable (∼86%) by 60 days after herbicide treatment (DAT), regardless of tillage treatment. However, addition of halosulfuron or imazamox to clomazone+ethafluralin generally improved redroot pigweed and common waterhemp control in no-tillage and conventional tillage compared with clomazone+ethafluralin alone; common cocklebur control was improved with addition of halosulfuron only to clomazone+ethafluralin. Although pumpkin fruit numbers in the weed-free control did not differ (P > 0.05) from tank mixtures of clomazone+ethalfluralin with halosulfuron or imazamox, reductions in pumpkin fruit size (30–35%) and yields (18–20%) were observed for these herbicide treatments compared with the weed-free control. This research indicates that cover crops, such as winter rye, can be successfully integrated in no-tillage pumpkin production systems along with herbicides to improve weed management.