Search Results

You are looking at 1 - 10 of 88 items for :

  • HortTechnology x
Clear All

fruiting French-American hybrids to dicamba is of particular interest to Missouri growers because hybrids are the predominant cultivars grown. The movement of dicamba to areas with sensitive grapevines may occur via particle drift or vapor drift. Particle

Open Access

(A) leaf transpiration (E) and (B) leaf vapor pressure deficit (VPD) after the first year of transplant under different coverings [enclosed screen houses and open-air (control)] and planting methods (in-ground and container-grown). The purpose of

Full access

Vapors of several common vinegars containing 4.2% to 6.0% (= 2.5 to 3.6 mol·L-1) acetic acid effectively prevented conidia of brown rot [Monilinia fructicola (G. Wint.) Honey], gray mold (Botrytis cinerea Pers.:Fr.), and blue mold (Penicillium expansum Link) from germinating and causing decay of stone fruit (Prunus sp.), strawberries (Fragaria ×ananassa Duchesne), and apples (Malus ×domestica Borkh.), respectively. Fruit were fumigated in 12.7-L sealed containers in which vinegar was dripped on to filter paper wicks or vaporized by heating from an aluminum receptacle. Vapor from 1.0 mL of red wine vinegar (6.0% acetic acid) reduced decay by M. fructicola on `Sundrop' apricots (Prunus armeniaca L.) from 100% to 0%. Similarly, vapor from 1.0 mL of white vinegar (5.0% acetic acid) reduced decay in strawberries by B. cinerea from 50% to 1.4%. Eight different vinegars, ranging from 4.2% to 6.0% acetic acid, of which 0.5 mL of each vinegar was heat-vaporized, reduced decay by P. expansum to 1% or less in `Jonagold' apples. The volume of heat-vaporized white vinegar (5.0% acetic acid) necessary to reduce decay by P. expansum on `Jonagold' apples to zero was 36.6 μL·L-1 of air. Increasing the number of conidia on the apple surface reduced the effectiveness of vinegar vapor. The number of lesions caused by P. expansum on `McIntosh' apple decreased exponentially with increasing time of fumigation, approaching zero after about 6 hours. These results suggest that vinegar vapor could be an effective alternative to liquid biocides such as sodium hypochlorite for sterilization of surfaces contaminated by conidia of fungal pathogens.

Full access

Acetic acid (AA) fumigation of rootstocks and dormant shoots was explored as a method of eliminating plant pathogens from propagation material. Dormant shoots were tested in early winter to determine the rate of AA vapor that they could tolerate before being damaged. Apricot (Prunus armeniaca), apple (Malus ×domestica), and peach (Prunus persica) shoots collected from a single site in Dec. 1999 tolerated 30, 12, or 6 mg·L–1 AA, respectively. Vineland 3 (V3) and Malling-Merton 106 (MM.106) rootstock liners fumigated with 1 mg·L–1 AA were adequately surface-sterilized although the effect on growth was not recorded. A similar experiment with Malling 9 (M9) rootstocks showed that 12 mg·L–1 AA would eliminate most surface microorganisims from roots although it delayed shoot growth when the trees were planted. The higher 15 mg·L–1 rate delayed tree growth and appeared to kill some trees. The 12 mg·L–1 rate prevented growth of Erwinia amylovora and Pseudomonas syringae pv. syringae bacteria on shoots even when an enrichment technique was used to detect them. Finally, when 96 `Jonagold' apple shoots known to be infected by Podosphaera leucotricha were fumigated with AA in 2001, none developed powdery mildew, although 99% of the control shoots did. These promising results suggest that further research should be done toward adapting AA fumigation for use by commercial nurseries.

Full access

desiccation injury. Kozlowski (1976) stated that such injury occurs when a large vapor pressure deficit or solar radiation load at low temperatures results in a rate of water loss from aboveground parts of the plant that exceeds the rate of water uptake and

Full access

radiation, vapor pressure, and number of frost days in April and May. Derived indices include GDD as described by Winkler et al. (1974) and RPMT as described by Gladstones (1992) . Units of measure and calculation method for climatic variables are

Full access

( Munnecke and Van Gundy, 1979 ). Soil temperature, soil moisture, microbial activity, the ratio between mixed materials, and vapor pressure of a substance are factors that determine the fate and efficacy of a pesticide in soil. Soil fumigants are substances

Open Access

temperature (21 ± 1 °C) in a plastic chamber that was sealed to minimize the loss of etridiazole to the vapor phase ( Ioannou and Grogan, 1984 ). Radial growth on two axes was measured 3 d post inoculation. There was one plate per etridiazole concentration for

Full access
Author:

Of 18 commonly used adjuvants evaluated on pecan [Carya illinoinensis (Wangenh) K. Koch], a few exhibited potential for substantially suppressing net photosynthesis (A) and the conductance of foliage to water vapor (g sw ) when used within their recommended concentration range; however, most provided no evidence of adversely influencing A or g sw . Suppression of gas exchange by certain adjuvants persisted at least 14 days after a single application. The recently developed organosilicone-based surfactants generally exhibited the greatest potential for suppression. These data indicate that orchard managers should consider the potential adverse influence of certain adjuvants when developing orchard management strategies.

Full access

Three different rain protective covering methods for sweet cherry (Prunus avium) trees were tested with uncovered trees as control. The covers were a pitched cover mounted permanently, a similar cover mounted only when raining, and a permanent umbrella type enveloping the top and sides of single trees. Covers were mounted 3 weeks before and throughout the harvest period in two seasons with different weather conditions. All three covering methods increased the amount of marketable fruit from 54% on uncovered to 89% on covered trees in mean of 2 years. Fruit from umbrella covered trees had lower soluble solid content, lower juice color and lower ripeness compared with fruit from all other trees, reflecting the different microclimate in these trees such as frequently higher maximum temperatures and greater vapor pressure. The two pitched covers produced no significant changes in microclimate or internal fruit quality compared with uncovered trees.

Full access