Michael D. Orzolek

Drip chemigation of imidacloprid under plastic mulch increased yield and decreased leaching caused by rainfall.

Muskmelons were grown on raised beds and imidacloprid was applied to control cumber beetles. The imidacloprid was applied as a band on bare soil, a single chemigation under plastic mulch, and as split chemigation under plastic mulch at three levels: label rate, reduced rate, and zero rate (control). Muskmelon yield increased ten-fold when imidacloprid was drip chemigated under black plastic mulch as compared to no chemigation and no plastic mulch. A four-fold yield increase resulted from plastic mulch alone while a 2.5 times yield increase resulted from imidacloprid alone. The reduced rate of imidacloprid produced the same weight of marketable melons as the label rate when a single dose of the pesticide was applied after transplanting. During a heavy rainfall period, drip chemigation of imidacloprid under plastic mulch prevented pesticide leaching through the root zone and pesticide transport via soil erosion off the beds.

Effect of Row Spacing and Herbicides on Burcucumber (Sicyos angulatus) Control in Herbicide-Resistant Corn (Zea mays)'

Abstract: Experiments examining burcucumber management in glufosinate-resistant (GR) and imidazolinone-resistant (IMI) corn were conducted in 1997 and 1998 in southeastern Pennsylvania. GR corn was planted in 38- and 76-cm rows, and postemergence (POST) treatments of glufosinate and glufosinate plus atrazine were applied to corn at the V4 or V5 growth stage. In a second study, IMI corn was planted in 76-cm rows, and 15 preemergence (PRE) and POST herbicide programs were evaluated. Herbicide treatments included RPA-201772, CGA 152005, simazine, imazethapyr plus imazapyr, imazamox, chlorimuron plus thifensulfuron, nicosulfuron plus rimsulfuron plus atrazine, CGA 152005 plus primisulfuron, and combinations with atrazine. Burcucumber germinated throughout the growing season, with greatest emergence occurring in early June, gradually decreasing to minimal emergence by mid-July. Glufosinate alone controlled burcucumber 79 to 90% 7 weeks after planting (WAP) regardless of application timing or row spacing. By 10 to 13 WAP, control was 82% or less due to lack of residual control and new burcucumber emergence. Row spacing had little effect on burcucumber emergence or control and appears to have little impact on burcucumber management in corn. In general, PRE herbicide programs were less effective than POST programs, although PRE treatments containing atrazine equaled some POST herbicides. POST-applied chlorimuron plus thifensulfuron, nicosulfuron plus rimsulfuron plus atrazine, and CGA 152005 plus primisulfuron controlled burcucumber greater than 80 and 90% in 1997 and 1998, respectively. Imazethapyr plus imazapyr and imazamox applied POST controlled burcucumber 66% 10 WAP. Adding atrazine to POST herbicide programs did not increase control, with the exception of imazethapyr plus imazapyr. Nomenclature: Atrazine; chlorimuron; glufosinate; imazamox; imazapyr; imazethapyr; RPA-201772 (proposed name, isoxaflutole), [5-cyclopropyl-4-(2-methyl-sulphonyl-4-trifluoromethyl-benzoyl)isoxozole]; nicosulfuron; primisulfuron; CGA 152005 (proposed name, prosulfuron), {1-(4-methoxy-6-methyl-triazin-2-yl)-3-[2-(3,3,3,-trifluoropropyl)-phenyl-sulfonyl]urea}, rimsulfuron; thifensulfuron; burcucumber, Sicyos angulatus L. #3 SIYAN; corn, Zea mays L. Additional index words: Cultural control, herbicide-resistant crops, weed emergence. Abbreviations: EPOST, early postemergence; GR, glufosinate resistant; HRC, herbicide-resistant crops; IMI, imidazolinone resistant; MPOST, midpostemergence; POST, postemergence; PRE, preemergence; WAP, weeks after planting.

Effect of Tillage, Row Spacing, and Herbicide on the Emergence and Control of Burcucumber (Sicyos angulatus) in Soybean (Glycine max)1

Abstract: An experiment was conducted in 1998 and 1999 in southeastern Pennsylvania to examine the effect of tillage and soybean row spacing on burcucumber emergence and growth. A second experiment evaluated postemergence (POST) soybean herbicides on burcucumber control. In the tillage and row spacing study, a glyphosate-resistant soybean variety was planted in no-till and reduced-tillage systems in 38- and 76-cm row spacings. In the POST herbicide experiment, chlorimuron, glyphosate, CGA-277476, thifensulfuron, and several combinations of these herbicides were applied at two different POST application timings in 38-cm row soybean planted in a reduced-tillage system. In the tillage and row spacing study, burcucumber emergence was greatest starting in late May through mid-June and mostly ceased by early July, regardless of tillage system or row spacing. Although there was no difference in germination period in either tillage system, preplant tillage increased the number of emerged plants by 110% in 1997 and 70% in 1998 compared to the no-till system. Row spacing had no effect on burcucumber emergence or biomass production. In general, most POST herbicide programs controlled burcucumber, and there was no difference between early POST and mid-POST application timings. Chlorimuron at 13 g ai/ha, chlorimuron plus thifensulfuron, glyphosate, glyphosate plus chlorimuron, and glyphosate plus CGA-277476 provided 87% or greater control of burcucumber 12 wk after planting. These herbicides reduced burcucumber density and biomass by more than 56% in 1997 and 96% in 1998. Nomenclature: CGA-277476 (proposed name, oxasulfuron), 2-[[[[[4,6-dimethyl-3-pyrimidinyl]amino]carbonyl]amino] sulfonyl]benzoic acid, 3-oxetanyl-ester; chlorimuron; glyphosate; thifensulfuron; burcucumber, Sicyos angulatus L. #3 SIYAN; soybean, Glycine max (L.) Merr. Additional index words: Cultural control, emergence period, herbicide application timing, herbicide-resistant crops. Abbreviations: EPOST, early postemergence; GDD, growing degree days; LPOST, late postemergence; MPOST, mid-postemergence; POST, postemergence; WAP, weeks after planting.

Effect of establishment date and crop competition on burcucumber fecundity.

Abstract An experiment examining the effect of burcucumber emergence date and corn competition on burcucumber fecundity was conducted in 1997 and 1998 in central Pennsylvania. Burcucumber seedlings were transplanted in the field in approximately 10-d intervals starting in late May through mid-August with or without competition from corn. Burcucumber plants grown without competition from corn produced 716 g dry matter and 4,500 seeds plant−1 in 1997 and 607 g dry matter and 1,800 seeds plant−1 in 1998. Biomass was greatest for plants established in late May, whereas seed production was greatest for plants established in mid-June. Although seed numbers were reduced in comparison to the May and June establishment periods, plants established as late as August still produced seed. Burcucumber established in corn produced 96% less dry matter and seed than the plants in a noncompetitive environment in both years of the study. Although the growth and seed production of burcucumber grown in corn was drastically reduced, plants established in mid-July still produced seed. Nomenclature: Burcucumber, Sicyos angulatus L. SIYAN; corn, Zea mays L.

Production of Drip Irrigated Potatoes as Affected by Plastic Mulches and Row Covers

ABSTRACT Field studies were conducted during 1998 and 1999 to determine the effect of different color plastic mulches and row covers on total and marketable yield and US grades of three varieties of potatoes, ‘Kueka Gold’, ‘AF1437-1’ and ‘Dark Red Norland’. Although there was an observed increase in the rate of emergence and growth of the potato plants with row covers, there was no significant effect on yield of any of the varieties. In both years all mulch treatments significantly increased marketable yields compared to no mulch. In 1998, yields of ‘Dark Red Norland’ showed a statistically significant difference between mulch color, with metallized silver and red being higher than black. In 1999, both total and marketable yields of ‘Dark Red Norland’ were significantly higher with the use of metallized silver rather than black mulch. For ‘AF1437-1’ total yield, with the use of metallized silver, was significantly higher than that of red mulch, and for marketable yield only metallized silver was significantly higher than for black mulch. Metallized silver mulch resulted in the highest marketable yields for all varieties of potatoes.

Plant density as related to fertilizer needs for processing and fresh market tomatoes

Abstract The effects of higher density plantings on tomatoes (Lycopersicon esculentum Mill.) at three nutritional levels were evaluated over two years. At each of two commercial sites, four in‐row spacings were combined with three fertilizer treatments in a split‐block design with six replications. Increasing plant density of the processing cultivar, ‘U.S. 68’, by changing spacing from 23 cm in single rows to 30 cm in double rows (46 cm apart) increased total and vine yields substantially, lowered yield/plant and decreased fruit weight slightly. Decreasing spacing to 23 cm in double rows did not further increase total yield but yield/plant was reduced. At all spacings, fertilizer banded at 56N‐56P‐56K kg/ha increased total fruit and vine yields and increased yield/plant but reduced mean fruit weight. The higher banded rate, 112N‐112P‐112K kg/ha, showed few trends towards further effects. Reducing spacing of the fresh market cultivar, ‘Count II’, from 76 to 30 cm in single rows substantially increased tota...