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  • Author or Editor: R.A. Damon Jr. x
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Abstract

Hay mulch applied only the year of planting under ‘Richhaven’ peach trees reduced foliar injury following annual applications of dichlobenil. Dichlobenil residues were greater than those of its breakdown product, 2,6-dichlorobenzamide (BAM), in mulch and at 0-15 cm soil depth under mulch. Mulch did not reduce amount of dichlobenil in soil. Only dichlobenil at 13.44 kg/ha, twice the rate labeled for usage under fruit trees, applied on mulch residue partially prevented an influx of annual weeds.

Open Access

Abstract

In greenhouse studies with radish (Raphanus sativus L.), KNO3, (NH4)2SO4, urea, dried sewage sludge, and dried cow manure were applied at 200, 400, and 800 mgN/1,200 g soil with 0 or 10 ppm of nitrapyrin. Soil analysis for pH, NO 3 and NH 4 + indicated that nitrification was inhibited throughout the growth (38 days) of the plants. Nitrogen deficiency limited plant growth at the 2 low rates of application of organic fertilizers. With the ammoniacal fertilizers, NH 4 + toxicity restricted root and shoot growth at the highest rate of N and especially in the presence of nitrapyrin relative to the KNO3 regimes. An interaction of nitrapyrin with the organic fertilizers limited root growth. This restriction was attributed partially to NH 4 + toxicity. Some indication of nitrapyrin toxicity was suggested by plant foliar appearance with the organic fertilizers but not with the inorganic sources. Ca and Mg concentrations varied with treatment, with increased rate of N and nitrapyrin addition sharply restricting their accumulation, especially with the ammoniacal and organic fertilizers. Percentage of K in the plants changed in a reciprocal manner to that of Ca or Mg. Compositional changes suggested that NH 4 + toxicity was a major factor causing a limitation of growth with the combination of nitrapyrin with ammoniacal or organic fertilizers.

Open Access

Abstract

Response of ‘Jerseyland’ peach trees to 3 consecutive yearly herbicide applications of 2-chloro-4,6 bis (ethylamino)-s-triazine (simazine) and sodium salt of 2,2-dichloropropionic acid (dalapon) alone and in combination was determined. The data included weed control, tree growth, fruit size, yield and leaf N, K, Ca and Mg content. The herbicide combination of dalapon at 4.25 lb ai/acre and simazine at 3.2 lb ai/acre gave the best weed control. The partial reduction in weed population was of no benefit to tree growth, fruit size, yield and nutrition. Simazine did not alter the chemical composition of the leaf or affect growth, fruit size and yield, as compared with either dalapon or the mowed control.

Open Access

Abstract

EM VII, EM IX AND MM 106 apple rootstocks were grown under greenhouse conditions in cans containing soil-incorporated simazine at concentrations of 0–6 ppm. In general, except for severity of foliar injury, the rootstocks responded similarly to simazine. Least foliar injury occurred on MM 106 rootstocks and the most injury on EM VII. Fresh weight increases indicated, however, that this difference may be of no practical significance.

Simazine levels of 1 and 2 ppm improved above-ground growth and increased total leaf nitrogen (N) but suppressed root growth. At concentrations of 3 ppm and higher, simazine suppressed both above-ground growth and root growth but markedly increased leaf N.

Open Access

Abstract

Ethephon [(2-chloroethyl) phosphonic acid] at rates of 100 to 1000 ppm caused fruit abscission of apples (Malus pumila Mill. cv. Cortland and Mutsu) when applied 26 to 44 days after full bloom. Ethephon alone or in combination with SADH (succinic acid 2,2-dimethylhydrazide) caused fruit abscission of ‘Early McIntosh’ when applied 30 days after full bloom. When sprayed shortly after completion of June drop, no abscission occurred. Although no fruit abscission followed the post-June drop treatment, flower bud initiation was increased. SADH appeared to enhance the fruit abscission capabilities of ethephon.

Open Access

Abstract

Annual applications of 2,6-dichlorobenzonitrile (dichlobenil) for 6 consecutive years at recommended rates caused yellowing of apple leaf margins (LMY). LMY appeared in mid-June or later and increased in severity as the season progressed. Severity of LMY was positively associated with individual trees throughout the study. Comparisons between control and dichlobenil-treated trees showed no differences in tree growth and yield, although they were sometimes negatively correlated with LMY severity.

Open Access

Abstract

Shoot growth and fresh wt of greenhouse-grown EM VII clonal apple rootstocks in 1970 were reduced by 1.5 ppm soil-incorporated dichlobenil. Concentrations of 6.0 ppm and higher prevented growth.

No leaf margin yellowing (LMY) was observed in 1970, but in 1971 it occurred following placement of 3 clonal rootstocks outdoors. EM VII produced the most shoot growth and EM IX the least. EM IX produced the least fresh wt increase, while those of EM VII and MM 106 were equivalent. EM VII had more LMY than the other 2 rootstocks.

The responses of the 3 rootstocks to several concn of dichlobenil were similar. Dichlobenil concn of 0.2 and 0.4 ppm increased fresh wt, largely due to stimulation of root growth. Concentrations of 0.8 ppm and more of dichlobenil suppressed growth.

Open Access

Abstract

The influence of Mailing (M)26, M9, M27 rootstocks and stempiece/rootstock combinations M9/Malling-Merton (MM)106, M9/MM111, M27/MM106, and M27/MM111 on growth, leaf nutrition, and fruit quality of ‘Empire’ apples (Malus domestica Borkh.) was evaluated. After 8 growing seasons, height and spread of trees on M26, M9/MM106, M9/MM11, M27/MM106, and M27/MM111 were similiar and were greater than those of trees on M9 and M27. Mn concentration in leaves from trees on M27 was higher than that of leaves from trees on other rootstock and stempiece/rootstock combinations. Production of trees on M26, M9/MM106, and M27/MM106 was greater than that on M9/MM111, M9, and M27. When fruitfulness was related to trunk area, trees on the various rootstock and stempiece/rootstock combinations did not differ in production efficiency. Effect of rootstock or stempiece/rootstock on fruit size was inconsistent. Fruit from trees on M27/MM111 entered in to their climacteric later than those from trees on M26 and M 27 for 2 years and from trees on M9 and M9/MM106 for 1 year, but the delay was small. No fruit flesh firmness differences were detectable. Soluble solids content of fruit from trees on M27 was higher than that of fruit on M26, M9/MM111, and M27/MM111. Senescent breakdown was more prevelant in fruit from trees on M26 than on M9, M27, M9/MM111, and M27/MM111.

Open Access