Wesley R. Autio

Summer Pruning as a Method for Reducing Flyspeck Disease on Apple Fruit

Summer pruning of apples, as opposed to the conventional commercial practice of dormant pruning, consistently reduced the incidence of flyspeck on apple fruit by approximately 50% in each of 2 years in trees where no fungicides were applied. In commercial orchard blocks using fungicides, summer pruning also produced a slight but significant decrease in disease severity. There appear to be at least two mechanisms contributing to decreased flyspeck incidence and severity in summer-pruned apple trees. Summer pruning resulted in a small change in the apple canopy microclimate, decreasing the hours of relative humidity >95% in the canopy by 63% and increasing the evaporative potential. Summer pruning also resulted in improved spray deposition in the upper two-thirds of the tree canopy when applications were made with an airblast sprayer.

Second-level integrated pest management in commercial apple orchards

As historical background helpful to understanding current concepts and practices of apple pest management, we review the origin and rise of key pests of apple in North America and the evolution of approaches to their management, culminating with the concept of integrated pest management (IPM). We propose four levels of integration of orchard pest management practices. First-level IPM integrates chemically based and biologically based management tactics for a single class of pests, such as arthropods, diseases, weeds or vertebrates. Second-level IPM, the focus of our effort here, integrates multiple management tactics across all classes of pests. We describe components of second-level IPM for Massachusetts apple orchards, which are threatened each year by an exceptionally broad range of injurious pests. We illustrate the tentative advantages and shortcomings of second-level IPM using 1993 data from six commercial orchard test blocks. Our predominant approach was to use chemically based tactics for controlling arthropods, diseases and weeds early in the growing season, and afterwards to rely exclusively (for insects) or largely (for other pests) on biologically based tactics, such as cultural, behavioral, and biological controls. Compared with nearby first-level IPM blocks, insecticide use in 1993 was reduced substantially (about 30%), with only slightly more insect injury to fruit and little difference in populations of foliar insect pests. The results for mite pests and diseases were less encouraging although summer pruning significantly reduced disease injury caused by flyspeck. We discuss how second-level IPM poses special biological or operational challenges to apple pest management practitioners. The concept has merit, but refinements are necessary before it can be recommended broadly to commercial apple growers in Massachusetts as an economical and reliable alternative to first-level IPM.

Disease-management components of advanced integrated pest management in apple orchards

Reducing fungicide use in commercial apple orchards is particularly problematic, although success would positively effect other aspects of orchard ecology, primarily arthropod management, and may alleviate ecological and food-safety concerns. Methods for reducing fungicides were tested in the context of advanced integrated pest management (IPM), in which arthropod pests are managed with minimal use of pesticides following the petal-fall stage of apple growth. The potential ascospore dose (PAD) method for predicting inoculum density of Venturia inaequalis, which causes apple scab, was used in conjunction with ascospore-maturity evaluation and ergosterol-biosynthesis-inhibiting fungicides to manage scab in advanced IPM blocks. In 78% of the cases studied, PAD indicated growers should delay the first fungicide application, but growers actually followed this recommendation in only half of these cases. Where growers followed the recommendation, they applied significantly less fungicide, saving an average of over one application during the primary apple scab season, a 26% reduction. A combination of summer pruning and limited captan use was recommended for management of flyspeck (caused by Schizothyrium pomi) and sooty blotch (caused by three associated fungi). Growers generally followed the advanced IPM recommendations, and during the summer applied 34% less fungicide in the advanced IPM blocks. The program showed that growers could achieve significant fungicide reductions in apples using these methods, although it also indicated that they were sometimes reticent to implement them.

Timing of partial defoliation affects carbohydrate concentration of vegetative tissues and concentration of phenolics in berries of potted De Chaunac (Vitis sp.) grapevines

Partial defoliation of grapevines often increases fruit phenolic content; however, improved light interception by fruit and possible improved photosynthetic efficiency of leaves are confounding factors. In this study, potted De Chaunac grapevines were partially defoliated at three phenological stages, but cluster light environment was unaffected. Partial defoliation at berry set significantly reduced glucose and fructose concentrations in the leaf/shoot tissue, and also reduced total flavonols and total phenolics in the fruit. Vines partially defoliated pre-harvest had increased sucrose concentration in the leaves and roots, increased glucose in the roots, and produced fruit with improved total anthocyanins compared to the control. Key words: Grapevines (French hybrid), carbohydrates, phenolics

Effects of Repeat Annual Applications of Dichlobenil on Weed Populations and Yield Components of Cranberry1

To address grower concerns that repeated use of dichlobenil could negatively affect cranberry productivity, field studies were conducted at two commercial farms in either high weed density (HW) or low weed density (LW) areas. Data from 4 yr of repeat annual applications of 0, 1.8, and 4.5 kg ai/ha dichlobenil indicated minimal negative impact on cranberry vines. Herbicide application did not affect upright productivity, leaf biomass production, percent fruit set, or other yield parameters adversely; in addition, no improvement in these parameters was noted. Although the interaction of herbicide application with weed density on cranberry root length varied with sampling date, no consistent trend (adverse or positive) was seen. The presence of weeds, rather than herbicide application, was the important determinant of yield. Vines in LW areas produced more marketable fruit and had higher percentage of fruit set than vines growing in HW areas. Repeat annual applications of dichlobenil on commercial cranberry beds may be considered as part of a viable integrated weed management program with no adverse effect on crop growth or yield. Nomenclature: Dichlobenil; cranberry, Vaccinium macrocarpon Ait. Additional index words: Herbicides, root length, vegetation survey, weed community. Abbreviations: HW, high weed density; LW, low weed density.

Handheld Flame Cultivators as a Management Option for Woody Weeds

Abstract Dewberry is a weed found on cranberry bogs that spreads quickly, causes high yield loss, and has no effective management strategy. Finding options to manage damaging perennial weeds in a perennial crop system, such as cranberry, is key to long-term industry sustainability. This study presents preliminary data on the use of flame cultivation (FC) in cranberry weed management. Utilizing weeds transplanted from commercial cranberry farms to a prepared area at the UMass Cranberry Station, we evaluated three handheld propane-fueled FC instruments: infrared torch, open flame torch, and an infrared torch with a spike. A single, midsummer exposure (zero, low, medium, or high duration) with each FC was tested. The industry standard of using a single wipe application of an herbicide solution (111 g L−1 ae glyphosate, isopropylamine salt) was also included in the evaluation. Dewberry shoot, root, and total biomass decreased linearly as exposure increased; the effect of FC tool type was not significant. Data indicated that, regardless of the specific torch utilized, spot treatment with FC reduced dewberry biomass. The results of this exploratory study suggest that FC may offer an alternative technique for managing woody weeds and that further research is warranted. Nomenclature: Glyphosate; dewberry, Rubus spp.; cranberry, Vaccinium macrocarpon Ait.

Utilizing Mushrooms to Reduce Overall Sodium in Taco Filling Using Physical and Sensory Evaluation

This project investigated the use of integrating mushrooms into beef taco filling as a means to reduce overall sodium for food service applications. Initial product development used physical characterization analysis (moisture, yield, color, and texture) to determine initial threshold of mushroom inclusion with minimal differences against an all-meat control. Increasing mushroom inclusion increased moisture and yield before draining but decreased yield after draining, lightness, redness, and texture. Results showed that inclusion under 50% by weight minimized physical attribute deviation from an all-meat control. Additional physical analysis investigated a variety of other factors (mushroom type, blanching, and particle size) to determine if other attributing mushroom characteristics would yield statistical similarity to the all-meat control. Results showed that a formulation containing up to 45% mushrooms can be integrated into beef fillings using un-blanched, white button mushrooms with small grind (1 to 5 mm), which maximized mushroom usage while minimizing differences from the all-meat control. Additional sodium analysis showed that varying salt level in formulations did not affect physical characteristics and mushroom inclusion could not significantly reduce overall sodium level. Optimized mushroom samples were then fielded in a hedonic sensory study to untrained consumers to evaluate product liking attributes (overall liking, aroma, color, flavor, juiciness, saltiness, and texture). Samples with overall liking scores that closely matched the control were then fielded in a paired-preference test to determine acceptance. Consumers preferred a 45% mushroom with reduced sodium taco filling compared to its full sodium counterpart in a food service fielded paired-preference sensory test. PRACTICAL APPLICATION Although diet can significantly reduce the risk of heart disease, American consumers continue to eat detrimental diets high in fat and sodium. Products need to be made that decrease fat and sodium intake while still delivering acceptable taste. Mushroom substitution into meat-based products can be a strategy to develop products that can decrease fat and sodium consumption while increasing vegetable intake without compromising the quality and taste consumers demand. This research shows how consumers can accept meat-based products containing mushrooms with potential for direct food service application.

Tree Wardens and public grounds management in North America: Overseeding athletic fields with perennial ryegrass to promote safe playing surface

Responsibilities of the municipal/urban forester, or Tree Warden as the position is known in parts of the United States, may extend to a variety of widely used community green spaces that include gardens, landscapes and athletic fields. In recent years, the application of non-chemical, cultural methods pertaining to the management of publically accessible athletic fields has garnered growing interest. This is especially true as it relates to weed control and the maintenance of desirable turfgrass cover and safe playing conditions. Based on previous research, a demonstration field study was conducted over four growing seasons (2005–2008) to determine the effectiveness of weekly, repetitive (8×), late summer – early fall overseeding with varying rates of perennial ryegrass: 0, 1, 3 and 6 lbs 1000 ft−2. Overseeding at the highest rate (6 lbs 1000 ft−2) appeared to generate the greatest increase in desirable turfgrass cover during growing seasons that received adequate, well-distributed rainfall. The relationships between amenity and sports grass management and adjacent trees are considered.

Fertilizer Regime and Weed Pressure Minimally Influence Leaf Tissue Nutrient Levels during Cranberry Vine Establishment

Cranberry leaf tissue samples were analyzed annually over a 6-year period. Vines received varied nitrogen (N) fertilizer rates and were subjected to low or high weed pressure. With few exceptions, levels of N, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), manganese (Mn), iron (Fe), and boron (B) were sufficient during the 6-year period. Calcium and B concentrations in cranberry vines treated with low, medium, or high rates of N were greater in areas with high weed pressure than in areas of low weed pressure. Levels of Zn and Mn were higher and K was lower in tissue collected from high weed areas in 4 out of 6 years. Calcium, Mg, Zn, Mn, B, and Fe levels were negatively correlated with increasing N rate. Overall, application of various N rates did not adversely affect cranberry leaf tissue nutrient content during the first 6 years.