INCORPORATED VERSUS SUBSURFACE VERNOLATE FOR WEED CONTROL TN PEANUTS*

Abstract

Summary. Under dry field conditions, vernolate (S‐propyl dipropylthiocarbamate) incorporated by conventional methods controlled less yellow nutsedge (Cyperusesculentus L.) and injuied peanuts (Arachis hypogaea L., groundnuts) more than when injected in lines under the soil or subsurface‐applied through sweep applicators. In glasshouse studies, vernolate eliminated production of new nutsedge tubers if it was applied below the soil surface either 1 in. above or 1 in. below the parent tuber. Method of placement was less critical in determining control of most annual weeds. When averaged over two soil types and 2 years, peanuts yielded 14% more after subsurface applications than after incorporated treatments of vernolate. In comparison with the optimum subsurface placement, the yield from incorporation was significantly lower in three of four field studies, the reduced yields probably resulting from a combination of herbicide injury and poor weed control. Factors affecting the distribution of vernolate vapours (such as method of placement, soil type and amount of rainfall after treatment) apparently determine the differential toxicity of this herbicide. Neither market quality nor germination of peanut seed was adversely affected by vernolate treatment.

Yellow Nutsedge (Cyperus esculentus) Control in Peanuts (Arachis hypogaea)

“…No explanation can be given for the aberration. Previous research (10,12,14) has indicated that vemolate will control yellow nut sedge early season very well, but is less effective as the growing season progresses.…”

Response of Yellow Nutsedge and Soybeans to Bentazon, Glyphosate, and Perfluidone

“…Because the 3.8-cm band was more effective than the 7.6-cm band, possibly the optimum band placement is less than 3.8 cm for this weed in this soil. On the other hand, Hauser et al (6) have reported that, under dry conditions, yellow nutsedge was controlled better by banded vernolate than by incorporated treatments. Our results show young plants are easier to kill than old plants.…”

Effects of Nitrogen with Trifluralin and Vernolate on Soybeans

“…Hauser et al (6) reported that vernolate incorporated in the soil controlled yellow nutsedge (Cyperus esculentus L.) less and injured peanuts (Arachis hypogaea L.) more than verno-late applied as an injected or subsurface soil treatment. The average yield of peanuts (2 yr on two soil types) was 14% greater after subsurface application of vernolate than after in corporation of vernolate.…”