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  • Author or Editor: Thomas J. Monaco x
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Abstract

Dormant rooted cuttings of 6 cultivars of highbush blueberry (Vaccinium corynbosum L.) were treated one week after field planting with 6 preemergence herbicides. In all cultivars 2-chloro-4,6-bis(ethylamino)-striazine(simazine) significantly increased shoot growth and 2-(2,6-dichlorophenyl)-l,3-thiazinon-4 (TH4052) increased root growth.

Open Access

Tree fruit researchers and extension specialists from North Carolina (NC), South Carolina (SC), and Georgia (GA) have been collaborating informally for many years. There has been a desire to formalize some of these arrangements, and in late 1998 planning was intiated to develop an extension specialist position to cover orchard and vineyard floor management in NC, SC, and GA. Wayne Mitchem, who had this responsibility for NC as well as serving as the coordinator for the regional IR-4 field research center at NCSU, presented us with the opportunity to create a three-quarters time extension specialist position dealing solely with the management of weeds in tree fruits and vineyards on a regional basis. The proposal was presented to Extension Directors from NC, SC, and GA in Oct. 1998, and over the following 6 months a memorandum of understanding was developed among the three states to establish the position. The position is located in NC at the Mountain Horticultural Crops Research and Extension Center, Fletcher, and each of the states agreed to share equally in funding the salary. None of the three states had this expertise in their faculty and if the position were not created, we would have had a void in this important aspect of orchard and vineyard maintenance. In addition to weed manangement, the position will have responsibilty for conducting residue trials for the IR-4 program as it pertains to the labeling of minor use pesticides for tree fruits and vineyards.

Free access

Abstract

Oryzalin (3,5-dinitro N4, N4-dipropylsulfanilamide), oryzalin/chloramben (3-amino-2,5-dichlorobenzoic acid) combinations, and diphenamid (N,N-dimethyl-2,2-diphenylacetamide) were evaluated for their influence on root quality of sweet potato [Ipomoea batatas (L.) Lam.] at harvest and during storage. Mineral analysis and foliage dry matter were evaluated with no significant differences observed between the oryzalin rates, diphenamid, and the controls. Soluble carbohydrates, reducing carbohydrates, ascorbic acid, and carotene content were not influenced by the herbicidal treatments. Intercellular space values were all within an acceptable range at harvest storage. The 3 rates of oryzalin utilized were not detrimental to quality and comparable to the diphenamid, weedy control, and cultivated control treatments.

Open Access

Abstract

Chemical defoliation of cucumber (Cucumis sativus L.) vines was evaluated as a method for rapid screening of breeding lines. Six chemicals (dinoseb, diquat, ethephon, glufosinate, glyphosate, and paraquat) were used at one or 2 rates on one pickling and one fresh-market cucumber cultivar (‘Calypso’ and ‘Poinsett 76’, respectively) in 1983 to determine speed of vine defoliation and amount of fruit damage. Of the chemicals tested, paraquat at 0.6 kg/ha provided the most rapid defoliation (85% to 91% defoliation one day after treatment) but caused some bleaching and chlorosis of the fruit. If the fruit were rolled 180° during evaluation, the damage was not noticeable. Chemical defoliation of vines for simulated once-over harvest provided a rapid, labor-saving method, requiring only 42% of the time to evaluate each plot compared to the conventional method. The chemical defoliation method is especially useful for initial evaluation of populations and breeding lines for fruit yield and other horticultural characteristics.

Open Access

Abstract

Seventeen herbicide treatments used in the production of sweet potato [Ipomea batatas (L.) Lam.] seed roots were evaluated for their influence on transplant production the following season. Number of transplants/root at five harvests, total transplants/root, and transplants/100 g of root were not influenced by the herbicide treatments. Weight/transplant was influenced by the herbicide treatments only at the last harvest. Total transplant weight/root and total transplant weight/100 g of root also were not influenced by the experimental treatments. No visual deleterious effects on transplant production were observed with any of the herbicide treatments.

Open Access

Abstract

Seven vegetation management programs ranging from 100% cover of grass-dominated vegetation to bare soil were created on opposing north and south aspects. Nutrient contents of the herbaceous vegetation and soil were effected significantly by management programs, location in the plot (row and interrow), and time. The presence or absence of vegetation influenced vegetative uptake and leaching losses, resulting in differences among the vegetation management programs. In general, the upper soil (0- to 15-cm depth) with 100% vegetative cover contained more exchangeable Mg and less NO3 and available P than under bare soil. Exchangeable Ca was not affected by the management programs. Differences in growth form (grass or forb), perennial or annual vegetation, and percent bare soil accounted for the majority of differences in the nutrient content of the noncrop vegetation. Aspect did not affect any of the plant and soil parameters measured.

Open Access

Several inheritance experiments with bentazon herbicide-tolerant Capsicum annuum `Bohemian Chili' (BCH P1) and susceptible `Keystone Resistant Giant' (KRG, P2) and `Sweet Banana' (SB, P2) were conducted. Populations of plants at the three- to five-leaf stage were treated with a bentazon rate of 4.5 kg·ha-1. Tolerance expression was affected by environment and varied across experiments. F2 and BCP2 generations from both susceptible parent crosses fit the expected ratios for a single, dominant gene conferring tolerance. Reciprocal F1s showed a maternal effect on tolerance intensity not consistently observed in reciprocal BCP2s or at all in reciprocal F2s. Segregation ratios of reciprocal crosses, however, were not heterogeneous, based on x2 tests of observed ratios in seven of eight cases. Variable tolerance expression in expected homogeneous populations (P1, P2, and F1) and lower tolerance in BC3 families suggested that modifying factors affected tolerance. Analysis of genetic components of shoot height and fresh weight generation means showed significant digenic epistasis, primarily additive × dominance. Modifying genes that affect the major gene controlling tolerance in BCH are, therefore, present. The simple inheritance of bentazon tolerance, even though modifying factors were present, facilitated transfer of bentazon tolerance into KRG via backcrossing. Chemical name used: 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon).

Free access

Abstract

Seven vegetation management programs ranging from 100% cover of grass-dominated vegetation to bare soil were created on opposing north and south aspects. After 3 years, fraser fir [Abies fraseri (Pursh) Poir.] survival had decreased when grown in bare soil, compared to survival in the other management programs. Norway spruce [Picea abies (L.) Karst.] survival was not affected by the management programs. Maximum stem diameter and root growth of Norway spruce were obtained with a bare row regardless of the interrow vegetation. Root growth in fraser fir was similar to spruce, but bare soil was required for maximum stem diameter growth. Height growth in both species was affected little by treatment. Stem diameter and root growth were negatively correlated with above-ground herbaceous biomass in the row. Forbs interfered less than grasses with fraser fir and Norway spruce diameter growth. Norway spruce growth was not affected by aspect, but fraser fir was larger (height and stem diameter) on the south aspect when grown in bare soil.

Open Access