fered advantages in weed control by covering row middles more quickly than single rows. Peanut (Arachis hypogaea L.) in the USA is generally grown in Excessive vine growth of some virginia market types single rows spaced 91 to 102 cm apart. Research suggests that pod typically occurs in the Virginia-Carolina production reyield can be increased by growing peanut in twin rows (18-23 cm spacing) on beds spaced 91 to 102 cm apart. Prohexadione Ca (Ca gion. The digging efficiency frequently decreases when salt of 3,5-dioxo-4-propionylcyclohexanecarboxylic acid) increases rows are difficult to distinguish, and the prevalence of row visibility and in some instances increases pod yield and improves disease often increases when vine growth limits air market grade factors. Research was conducted to determine response

zide (Brown et al., 1973; Hsi and Davidson, 1980). Increases in fruit number per plant were found with apple Excessive vegetative growth of peanut (Arachis hypogaea L.) can (Malus spp.), grape (Vitis vinifera L.), broad bean (Vicia make digging and inverting operations less efficient. Reducing vine growth by applying a suitable plant growth regulator would be an faba L.), and tomato (Lycopersicon esculentum Mill.) efficient way to manage peanut vines. Pod yield, market grade factors, (Fisher and Looney, 1967; Looney et al., 1967; Read and gross economic value of peanut treated with prohexadione caland Fieldhouse 1970; Tukey, 1970; Younis and Elnur, cium (calcium salt of 3,5-dioxo-4 propionylcyclohexanecarboxylic 1970) treated with daminozide. Registration for damiacid) were evaluated at 19 sites in North Carolina during 1999 and nozide was cancelled in 1988. 2000. Experiments were also conducted at two locations each during Prohexadione Ca suppresses vegetative growth of 1999 and 2000 to determine the effect of prohexadione Ca, digging apple, rice (Oryza sativa L.), tomato, grain sorghum date, and lifting (shaking peanut vines after digging to remove soil [Sorghum bicolor (L.) Moench], wheat (Triticum aestibefore combining) on combined yield, market grade factors, gross vum L.), and oilseed rape (Brassica napus L.) (Byers economic value, seed germination, and pod loss of the virginia marketand Yoder, 1999; Grossman et al., 1994; Lee et al., 1998; type cultivar NC 12C. Prohexadione Ca at 140 g a.i. ha Ϫ1 , applied at 50% row closure and repeated 2 wk later, increased row visibility at Nakayama et al., 1992;Yamaji et al., 1991). Prohexadiharvest, pod yield by 310 kg ha Ϫ1 , and gross economic value of quota one Ca inhibits gibberellin biosynthesis by blocking peanut by $223 ha Ϫ1 when pooled over 19 sites. Prohexadione Ca kaurene oxidase and also increases the level of abscisic increased combined yield by 220 kg ha Ϫ1 and decreased percent pod acid and cytokinins in responsive species (Grossman loss by 4% regardless of digging date and lifting treatment compared et al., 1994). In vivo, the primary mode of action of with nontreated peanut. Prohexadione Ca did not affect maximum prohexadione Ca is inhibition of 3␤-hydroxylation of yield (sum of pods remaining in soil and on the soil surface and

Diclosulam is generally applied either PPI or PRE to peanut to control certain broadleaf weeds and suppress sedges. Research was conducted to determine efficacy and peanut response to POST applications of diclosulam at 9, 13, 18, and 27 g ai/ha. Efficacy of diclosulam was affected by application rate and environment. Common ragweed control ranged from 60 to 100%, entireleaf morningglory control from 56 to 100%, marestail control from 78 to 85%, and nodding spurge from 50 to 97%. Smooth pigweed and common lambsquarters were both controlled less than 35%. Diclosulam controlled yellow nutsedge and eclipta less than 70 and 80%, respectively. In separate experiments, diclosulam and imazapic controlled dogfennel more effectively than acifluorfen, bentazon, imazethapyr, lactofen, paraquat, or 2,4-DB. Visual estimates of peanut injury were 15% or less for all rates during both years. Peanut yield ranged from 3,340 to 3,730 kg/ha in 2002 and 5,230 to 5,820 kg/ha in 2003. Foliar injury and peanut pod yield were influenced by diclosulam rate, although no clear relation was evident. Cultivar and diclosulam rate did not interact with respect to visual injury or pod yield.

No abstract

Peanut digging efficiency is often reduced due to excessive vine growth. The plant growth regulator prohexadione calcium retards vegetative growth and improves row visibility by inhibiting internode elongation resulting in improved digging efficiency and in some instances increases in pod yield. The objective of this research was to determine the effects of prohexadione calcium on row visibility and pod yield of newly released and commercially available cultivars AT VC-2, Brantley, CHAMPS, Georgia Green, Gregory, Perry, Phillips, NC-V 11, NC 12C, Tamspan 90, and VA 98R and the breeding lines N02006, N01013T, and VT 976133. Although differences in row visibility were noted among cultivars, prohexadione calcium improved row visibility in almost every experiment regardless of cultivar. The cultivars NC 12C and Perry were more responsive to prohexadione calcium in terms of pod yield than NC-V 11 or VA 98R. Response of these cultivars was independent of digging date. In other experiments, prohexadione calcium improved row visibility of the cultivars AT VC-2, Gregory, NC-V 11, Perry, VA 98R, and Wilson, but did not increase yield when compared with non-treated peanut. In a final experiment, prohexadione calcium improved row visibility of the Virginia market type cultivars Brantley, CHAMPS, Gregory, and Phillips and the experimental lines N02006, N01013T, and VT 976133. Row visibility for the experimental line N01013T was improved at 2 of 4 sites by prohexadione calcium. In a final experiment, prohexadione calcium increased row visibility of Georgia Green, Gregory, and Tamspan 90 but did not affect pod yield of these cultivars.