Application of 2-chloroethanephosphonic acid (120 to 240 parts per million) to monoecious cucumber plants when the first true leaf was 2 centimeters in diameter has resulted in as many as 19 continuous pistillate nodes. Control of the flowering habit simplifies the production of hybrid seed and offers the possibility of enhancing cucumber yields.

The response of close-spaced, pickling cucumbers(Cucumis sativusL.) to preplant incorporation treatments ofO,O-diisopropyl phosphorodithioateS-ester withN-(2-mercaptoethyl)benzenesulfonamide (bensulide),N-butyl-N-ethyl α,α,α-trifluoro-2,6-dinitro-p-toluidine (benefin), and dimethyl tetrachloroterephthalate (DCPA) and preemergence applications of 4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline (nitralin) and the methyl ester of 3-amino-2,5-dichlorobenzoic acid (chloramben) has been evaluated over a 2-year period. DCPA and nitralin gave the best overall weed control, while benefin and the methyl ester of chloramben were less effective in controlling weeds. The poorest weed control performance was observed with bensulide. Nitralin, DCPA, benefin, and the methyl ester of chloramben caused crop injury if leaching rains followed application. Despite early herbicide injury, yields were usually not adversely affected.

No abstract

The effect of 2-chloroethanepliosphonic acid (ethrel) on the sex expression of pickling cucumbers was studied. Tests to determine concentrations, effect on sex expression, and yield potential were conducted in greenhouse and field situations. As many as 19 successive pistillate nodes were observed for the treated monoecious cultivar ‘SC 23’. The most effective concentrations of ethrel were 120, 180 and 240 ppm for these studies. These rates in single or multiple application resulted in the greatest number of continuous female nodes with the least shortening of internodes. A much lower concentration of 24 ppm had little effect as to stunting and only limited effect on sex conversion. Significant yield increases, as measured by value per acre, were obtained for 3 monoecious cultivars, ‘Model’, ‘SC 23’ and ‘Chipper’, treated with ethrel.

‘Jewel’ sweet potatoes [Ipomoea batatas (L.) Lam] were grown for 2 seasons on an Orangeburg loamy sand soil with 3 N sources, 3 K rates, and 2 N rates. NH4NO3 and Ca(NO3)2 were equivalent in influence on root quality at harvest and storage, but NaNO3 significantly reduced root dry matter content. With an increase in N rate from 101 to 202 kgN/ha, weight loss during storage increased and carbohydrate levels, dry matter content, and root intercellular space values decreased. An increase in K applications from 70 to 280 kg/ha reduced root dry matter content.