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  • Author or Editor: A. W. Johnson x
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Abstract

Effects of different nematicides on yields of sweetpotatoes and on root-knot nematode (Meloidogyne incognita) damage at two different locations were studied over a period of 3 years. Average yields of marketable size roots were significantly increased on Hartsells fine sandy loam from use of Penphene, D-D, Dowfume W-85, Telone, and Nellite; the increased yield from Furadan was nearly significant. All nematicides reduced the root-knot infection counts on steam-peeled roots and root-knot larvae per pint of soil at harvest. Furadan gave the best nematode control. Average' yields were increased on Alaga sand from use of Penphen, D-D, D-D + SD14647, Vorlex, Furadan, Temik, and Mocap. Average root-knot infection counts and root-knot larvae per pint of soil at harvest were significantly reduced by all nematicides used; the greatest reductions followed applications of Temik, Mocap, Furadan, and D-D + SD14647.

Open Access

Abstract

Different rates of N, P, and K on southernpea Vigna unguiculata (L.) Walp. grown for one-time harvest during 4 years in field experiments on Alaga sand (Typic Quartzipsamments) soil showed that N had the greatest effect on yield of mature green southernpeas. Pea yields increased to a maximum of 67 kg/ha of N. Soil test P ranged from high to extremely high in the untreated soil; therefore, fertilizer P did not affect yield. Yields were increased by K only in the location-year in which soil-test K was low. At 35 days there was an increase in leaf N concentration as the rates of N were increased from 34 to 101 kg/ha; at 49 days the N concentration was lower and was not affected by N rates. Increasing fertilizer rates of K increased leaf concentration of K at both 35 and 49 days. Fertilizer P did not affect N, P, or K concentration.

Open Access

Abstract

Millet, milo, soybean, crotalaria and Norman pigeon pea were used in conjunction with clean fallow and a nematicide (fensulfothion) for managing root-knot nematode populations in tomato (Lycopersicon esculentum Mill.) transplant production. Clean fallow was most effective in suppressing numbers of nematodes. After 2 years, numbers of nematodes increased to damaging levels and fallow was no longer effective for complete control even when used in conjunction with fensulfothion. After 4 years none of the crops used as summer cover crops alone or in conjunction with fensulfothion reduced numbers of root-knot nematodes in harvested tomato transplants sufficiently to meet Georgia regulations.

Open Access
Authors: and

Abstract

‘LaJewel’ is a late season peach for fresh and pick-your-own marketing, maturing about 15 days after ‘Elberta’. Fruits are freestone with yellow flesh. Resistance to bacterial spot [Xanthomonas campestris pruni (Smith) Young et al.] is high.

Open Access

Abstract

Combination treatments containing an organic phosphate or carbamate nematicide, a herbicide, and a fungicide on a common granule controlled root-knot nematodes and weeds and increased tomato (Lycopersicon esculentum Mill.) plant growth. Bay 68138 + diphenamid, ethoprop + diphenamid, Bay 68138 + pebulate + Dexon, fensulfothion + isopropalin + Dexon, Bay 68138 + isopropalin + Dexon, and ethoprop + isopropalin + Dexon completely controlled root-knot nematodes. Isopropalin and pebulate controlled FL pusley and crabgrass as effectively as diphenamid, the standard herbicide. Ethoprop + pebulate, fensulfothion + pebulate + Terrazole, ethoprop + pebulate + Dexon, and Bay 68138 + pebulate + Dexon were phytotoxic to tomato seedlings early in the growing season. Formulations containing a nematicide + herbicide + fungicide can be spread on the soil surface just before planting and incorporated with a power-driven rototiller to reduce unit production costs of tomato transplants. Production of uniform transplants free of nematodes and relatively free of weeds can facilitate mechanical harvesting.

Open Access

Abstract

Pepper (Capsicum frutescens L.) and summer squash (Cucurbita pepo var. melopepo (L.) Alef.) were grown in immediate succession in undisturbed beds using trickle irrigation with various treatments. Highest combined yield in metric tons/ha for both crops was obtained with film mulch + soil fumigation (117.6) followed by film mulch (112.3), soil fumigation (93.4) and control (69.0), respectively. Yield from the second crop was negatively correlated (r=−.87) with the degree of plant infection with root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood). Intensive production in this manner allows fixed costs to be defrayed over two crops thus increasing the magnitude of return per dollar invested. Multiple cropping of pepper and squash with trickle irrigation has an excellent potential in south Georgia provided nematodes and other soil-borne pathogens can be adequately controlled.

Open Access

Abstract

Marketable tomato yields were influenced more by applied N than by irrigation. Irrigation increased total marketable tomato yields only at the intermediate level. Average yields for the 3-year period by soil water regimes were about 58,300, 70,000, and 68,900 kg/ha for no, intermediate, and high irrigation, respectively. Applied N increased yields, but the increase was limited mainly to the lowest application rate (65 kg/ha) in 1971 and 1972, and to the 2 lowest rates (65 and 130 kg/ha) in 1973. Average yields for the test period by N application rates were about 53,500, 67,100, 69,900, 70,600 and 67,600 kg/ha for 0, 65, 130, 195, and 260 kg/ha rates, respectively. These data indicate that the best combination of N rate and soil water regime was 65 to 130 kg/ha of applied N and supplemental irrigation as needed to maintain 30% or more available water in 0 to 60 cm soil depth.

Open Access

Abstract

Magnesium sulfate applied as a soil amendment (34 kg Mg/ha annually for 3 years or a single application of 224 kg Mg/ha) increased leaf Mg 5 years after initial application. Dolomite increased soil pH and soil test Mg but not leaf Mg. Sulfate of potash magnesia and MgO increased soil test Mg and slightly, though insignificantly, increased leaf Mg. Single foliar sprays of MgSO4 and Mg(NO3)2 did not affect leaf Mg.

Open Access

Abstract

Four snap bean (Phaseolus vulgaris L.) breeding lines, resistant PI 165426, and 2 susceptible commercial cultivars were tested for resistance to root galling and root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) reproduction under greenhouse and field conditions. Root gall indices, reproduction indices, and numbers of eggs/g of root were significantly less on resistant lines than on ‘White Seeded Provider’ in 2 greenhouse tests. In field tests, soil treatment with the nematicide DBCP resulted in significant control. In nontreated plots, resistant bean lines had less root galls than ‘Early Gallatin’. Plots planted with resistant lines had fewer M. incognita larvae than those with ‘Early Gallatin’. Mean yield of pods from resistant lines in nontreated soil was about 3 times the yield of ‘Early Gallatin’. Yield of pods from treated and nontreated subplots were not significantly different. These results indicate that resistance is equivalent to soil fumigation for root-knot nematode control in snap beans.

Open Access