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Red raspberry (Rubus idaeus L. cv. Willamette) primocanes were artificially defoliated to various degrees and at two dates in each of 2 years to simulate defoliation caused by the twospotted spider mite (Tetranychus urticae Koch). The effect on primocane diameter, lateral length, yield and four yield components was determined. When defoliation occurred evenly along the length of the primocanes, and all floricanes and excess primocanes were removed in early Aug. 1989, yield was reduced 26% at 25%, 50%, and 75% defoliation and 55% at 100% defoliation compared with nondefoliated controls. The number of canes per stool, number of fruit per lateral, and weight per fruit were reduced when defoliation occurred earlier, in August rather than September, but the number of laterals per cane increased with early defoliation. The effect of increasing defoliation on plant growth and yield was generally nonlinear. When defoliation occurred in sections along the lower 2 m of all primocanes, and all floricanes and excess primocanes were removed in Nov. 1992, no significant differences in yield or three yield components were detected. The effects of primocane defoliation are not necessarily predictable, so T. urticae should be controlled before mite-induced defoliation occurs.
An accurate and efficient system for measuring and recording fruit quality data was developed. Utilizing this procedure and custom made instrumentation. two individuals can efficiently collect, measure and record the following data: apple fruit size (weight and diameter), % red skin color, length/diameter ratio, flesh firmness, soluble solids. seed count. and starch-iodine index at a rate exceeding 60 fruit/hour. If starch iodine and seed counts are eliminated, 100 fruit/hour rates can he achieved. One individual can test 40-50 fruit/hour.
Testing equipment/materials consist of a mechanical weight scale; custom made length/diameter ratio gauge; custom made flesh firmness instrumentation; refractometer; starch-iodine solution and pie pans; and an electronic data-logger. All data is manually entered. The use of custom equipment constructed from readily available parts combined with the UVM Fruit Testing Protocol, has greatly enhanced the speed and accuracy of testing, measuring and quantifying apple fruit quality data.
Apple scab, a fungal disease caused by Venturia inaequalis, is considered the most important disease of apple worldwide. The disease can be devastating, causing reduction in yield or making the apples unfit for the market. Currently, the production of marketable fruit from scab susceptible cultivars depends on the repeated applications of fungicides. Scab-resistant apple cultivars, which are genetically immune to apple scab, can offer a biological alternative to fungicide use. `Liberty,' was bred for immunity to apple scab; however, it is not immune to other apple diseases and pests. Research has been conducted during a 3-year project (1996–1998) to determine whether reduced fungicide programs adversely affect overall tree vigor, productivity, and fruit quality. Data collected include tree vigor (TCSA and time of leaf abscission), tree productivity (YE), and fruit quality (fruit firmness and disorders during storage). Results indicate no significant differences between the two treatments (reduced fungicide and no fungicide application) in most of the parameters measured. Based on fruit that were harvested and graded to commercial standards, the estimated gross monetary value of the crop does not show difference between treatments. These results could translate into an economic advantage for growers when one factors in the savings in fungicide purchases. In addition, there are also health and environmental advantages to reduced fungicide usage.
Divergent physiological responses to drought between and among accessions within Fragaria chiloensis (FC) and F. virginiana (FV) may result from differing responses to ABA produced during the drought. Excised leaves from an accession of each species as well as F. ×ananassa (FXA) `Tribute' and their interspecific hybrids were fed ABA at 0, 1, 10, 100, and 1000 nM via the cut petiole for 24 h before measuring transpiration rate. Transpiration rates of the FV accession and FV by FXA hybrid were relatively less responsive to ABA than any of the others tested. Foliar membrane competence of the FC and FV accessions, measured by the gTi method using excised disks, was reduced by ABA treatment in both species with a relatively greater effect on FV. A drought episode before sampling affected gTi values of FV but not FC. ABA treatment had no additional effect on gTi values of a previously droughted FC accession, while gTi values of a previously droughted FV accession were increased with ABA treatment. Thus, transpiration of the FV accession was less responsive to increasing ABA concentration than the FC accession, while membrane competence of the FV accession was affected more by both drought and ABA treatment applied separately or in combination than the FC accession.
Downy mildew (DM) is a serious foliar fungal disease of cucurbits. DM can cause yield losses for New Jersey growers if not properly controlled. In 2004, five chemical control programs were evaluated in a research trial at the Rutgers Snyder Research and Extension Farm (Hunterdon Co.). Materials evaluated were: 1) Phostrol, 5 pt/A; 2) Phostrol, 5 pt/A plus Bravo WS, 3 pt/A; 3) Flint WDG, 2 oz/A alternated with Bravo WS, 3 pt/A plus Nova 40W, 5 oz/A; 4) Maneb 75DF, 2 lb/A plus Champ Formula 2 Flowable, 1 1/3 pt/A; and 5) untreated control. All fungicide programs were applied weekly. Phostrol (Nufarm Americas, Inc.) is a new product with systemic mode of action that is newly labeled for cucurbits for control of DM, but not powdery mildew (PM). The active ingredients are mono- and dibasic-sodium, potassium, and ammonium phosphates. Phostrol and Phostrol plus Bravo were evaluated against industry standard fungicide programs which include alternating chlorothalonil + myclobutanil with strobiluron chemistries on a weekly basis. Fungicide applications were made weekly beginning at first observance of DM in the field on 23 July. Plots were rated for DM and PM incidence and extent of defoliation on 6 Aug. and 24 Sept. Phostrol plus Bravo applied on a weekly basis (7 to 10 days) provided the best control of DM, which appeared much earlier in the season than usual in northern New Jersey. Treatments Phostrol, Flint alternated with Bravo + Nova, Maneb + Champ reduced DM compared to the UTC. Maneb plus Champ provided the best control for PM. At harvest, fruit was graded and weighed. Marketable yield from Phostrol, Phostrol plus Bravo and Maneb plus Champ treatments was significantly higher than the UTC and Flint/Bravo plus Nova treatment. Handle quality was not affected by treatment.
The objective of this research was to evaluate the effects of vacuum cooling and temperature on the quality and storage life of mung bean sprouts (Vigna radiata L. Wilczek). Sprouts in micro-perforated bags were either not precooled or vacuum cooled to 9, 6, or 3 °C, and stored for 7 days at 1, 3, or 6 °C. Vacuum-cooled bean sprouts lost more weight than sprouts not precooled, and the weight loss was greater when the sprouts were cooled to lower temperatures. However, the total loss never exceeded 5% and no apparent signs of shrivel were observed. Vacuum cooling resulted in greater product freshness after 4 days of storage, but the effect was nonsignificant after 7 days. Storage temperature had greater influence on bean sprout quality than did cooling temperature, with greater freshness and whiter hypocotyls at the lower temperatures. However, blackening of cotyledons increased as the storage temperature decreased.
Cultivar and planting site are two factors that often receive minimal attention, but can have a significant impact on the quality of apple (Malus ×domestica) produced. A regional project, NE-183 The Multidisciplinary Evaluation of New Apple Cultivars, was initiated in 1995 to systematically evaluate 20 newer apple cultivars on Malling.9 (M.9) rootstock across 19 sites in North America. This paper describes the effect of cultivar and site on fruit quality and sensory attributes at a number of the planting sites for the 1998 through 2000 growing seasons. Fruit quality attributes measured included fruit weight, length: diameter ratio, soluble solids concentration (SSC), titratable acidity (TA), flesh firmness, red overcolor, and russet. Fruit sensory characteristics rated included crispness, sweetness, and juiciness, based on a unipolar intensity scale (where 1 = least and 5 = most), and acidity, flavor, attractiveness, and desirability based on a bipolar hedonic scale (where 1 = dislike and 5 = like extremely). All fruit quality and sensory variables measured were affected by cultivar. The two-way interaction of cultivar and planting site was significant for all response variables except SSC, TA, russet, crispness, and sweetness ratings. The SSC: TA ratio was strongly correlated with sweetness and acidity sensory rating, but was weakly correlated with flavor rating. The results demonstrate that no one cultivar is ideally suited for all planting sites and no planting site is ideal for maximizing the quality of all apple cultivars.
Researchers have collected a considerable amount of data relating to apple (Malus ×domestica) cultivars and rootstocks over the past 30 years, but much of this information is not easily accessible. The long-term goal of our working group is to increase access to this information using online technology available through eXtension. In eXtension, researchers and extension personnel are developing a community of practice (CoP) to increase the quality and amount of online information for individuals interested in our work [referred to as a community of interest (CoI)]. For this project, our CoI is broadly defined as commercial apple producers, nursery professionals, county extension educators, Extension Master Gardeners, home gardeners, and consumers. Our CoP is developing diverse educational tools, with the goals of increasing productivity, profitability, and sustainability for commercial apple production. Additionally, we will provide other members of our CoI access to research-based, reliable information on the culture of apples. We chose to begin our focus on cultivars and rootstocks adapted to the eastern United States and will add other U.S. regions as our resources and interest in our project grows.