SEEDLING GROWTH TOLERANCE OF CUCURBITS CROPS TO HERBICIDES STOMP AND ACETOCHLOR
Summary. Several species from the Cucurbitaceae family including muskmelon, watermelon, cucumber, pumpkin, and squash were used to evaluate their tolerance in a laboratory test to two herbicides (Stomp and Acetochlor) widely used in crop cultivation. The effects of concentration and site of herbicide action on the length of primary roots and hypocotyls as well as seedling fresh weight were studied. The results showed that the cultivars differed greatly in their sensitivity to the herbicide action. The difference in the growth responses was not only species-, but also cultivar-specific. In addition, there was a difference in the herbicide acting site on plants which depended on the kind of cucurbits crops. Based on the tolerance to the action of both herbicides the studied species can be classified as follows: watermelon, squash, pumpkin, muskmelon, cucumber. The tolerance differences of the studied cucurbits crops can be used in cultivation practice.
Response of Transplanted Watermelon (Citrullus lanatus) to Ethalfluralin Applied PPI, PRE, and POST
Field experiments conducted in 1992 and 1993 evaluated transplanted watermelon tolerance to ethalfluralin applied PPI, PRE (before transplanting), and POST (immediately after transplanting) at 1.2 or 2.4 kg ai/ha. Other treatments for comparison included the registered herbicides ethalfluralin POST-directed spray (PDS), ethalfluralin PDS followed by (fb) naptalam POST, bensulide plus naptalam PPI, and a nontreated check. All treatments controlled common lambsquarters and goosegrass 83 to 100% 2 and 6 weeks after treatment (WAT). Watermelon was injured 30 to 77% in 1992 and 14 to 83% in 1993 by ethalfluralin PPI or PRE at 1.2 or 2.4 kg/ha. Ethalfluralin POST was not injurious to watermelon. In 1992, watermelon treated with ethalfluralin POST at 1.2 and 2.4 kg/ha yielded 52 to 62% more fruit than watermelon from the nontreated check. In 1993, yield of transplanted watermelon treated with ethalfluralin POST was similar to that in the nontreated check.
Response of Squash to Irrigation, Nitrogen Fertilization, and Tillage Systems1,2

‘Dixie’ squash (Cucurbita pepo L. var. condensa) were subjected to factorial combinations of 2 irrigation levels, 4 N treatments, and 3 tillage methods on a Lakeland sand soil during 1978, 1979, and 1980. The greatest marketable fruit yield resulted from a combination of applying irrigation at 0.3 bar soil water tension, applying 22.5 kg N/ha through the irrigation system at 2, 3, 4, 5, and 6 weeks after planting, and preparing the seedbed by moldboard plow tillage. Yields were reduced 3 to 16% by either reducing the N rate, allowing a greater soil water tension before irrigating, or by the use of subsoil-bed or disk-harrow tillage system. A combination of subsoil-bed tillage and application of irrigation at 0.6 bar soil water tension resulted in the greatest yield when squash received a single N application after planting.