Delaware lima bean yields have averaged 1700 lbs per acre for the last 30 years. California averages 3500-4000 lbs per acre. Varieties M-15 and 1072 are used by both states for production. In an effort to increase lima bean yields in Delaware, the evaluation of the effect of weather events on plant development, the relationship of ethylene and abscission of reproductive structures, and the comparison of both California and Delaware lima bean production is being conducted. Preliminary observations of 1991 data show a difference in plant size and population between the two states. Although pods per plant are the same in both states, the number of pods per acre is greater in California. California yielded 4303 lbs. per acre and Delaware 1651 lbs. per acre. The average maximum and minimum temperatures in California was 92.7 and 60.7 degrees Fahrenheit respectfully compared to 83.1 degrees and 61.2 degrees Fahrenheit in Delaware.
Tracy Wootten and Ed Kee
In response to a national increase in the consumption of triploid (seedless) watermelons, seedless watermelon production in Delaware has increased to 43% of the total watermelon acreage. Cultural practices for triploid watermelon production are similar to seeded (diploid) types. However, poor seed germination, high seed costs, erratic performance, and inadequate varieties limited their adoption until the early 1990s in Delaware. Univ. of Delaware Cooperative Extension has worked with Delaware growers to develop a “recipe” for successful triploid production. Extension programs, such as on-farm demonstrations, research trials, educational seminars, and one-on-one consultations, have enabled producers to provide high-quality fruit and yields. Intensive management and marketing are the keys tosuccess as Delaware producers have become leaders of triploid production in the Northeast region. As demand for triploid watermelon continues to increase, extension will remain a vital part of the $4.5 million industry. Growers continually deal with marketing issues in a supply and demand-driven market. As more seedless are on the market and profits lessen, growers will have to be diligent in their marketing and management practices.
Edwin Kee and Tracy Wootten
U.S. crop loss from hail damage amounted to $246,443,391 in 1991. Premiums paid for hail insurance was $403,742,507. Despite the magnitude of this industry, the effects of varying levels of hail injury at different stages of plant growth is largely unknown for many vegetable crops. To further evaluate the effects of hail on strawberries, watermelons, and sweet corn, several studies were established in 1991 and 1992. Simulated hail applications were made at different rates and stages of crop growth. Total yields and marketable yields of strawberries were reduced by hail applications. All hail treatments reduced the number of marketable watermelons, except for the vegetative size light hail treatment in 1991. In 1992, the early treatments caused the most total yield reduction. All hail treatments reduced the percentage of marketable ears of sweet corn, except for the light application in the 13th leaf stage (early vegetative) in 1991. In 1992, additional treatments consisting of clipping all leaves were conducted. Clipping leaves at the early silking stage reduced marketable ears, indicating the loss of foliage adversely affected the growth of the ear. Clipping leaves just prior to harvest reduced the yield of Jubilee, but not Silver Queen.
Ed Kee, Tracy Wootten, and James Glancey
James L. Glancey, Edwin Kee, and Tracy Wootten
The vegetable industry is important to our nation as a provider of nutritious and safe food directly consumed by our citizens. It is also critical to a rich and vigorous national agriculture. During the 20th century, engineering innovations coupled with advances in genetics, crop science, and plant protection have allowed the vegetable industry in the U.S. to plant and harvest significantly more land with higher yields while using less labor. Currently, fresh and processed vegetables generate 16% of all U.S. crop income, but from only 2% of the harvested cropland. Yet, many of the challenges in production that existed a century ago still exist for many crops. Perhaps the most significant challenge confronting the industry is labor, often accounting for 50% of all production costs. A case study of the mechanized production system developed for processed tomatoes (Lycopersicon esculentum) confirms that systematic methodology in which the machines, cultural practices, and cultivars are designed together must be adopted to improve the efficiency of current mechanized systems as well as provide profitable alternatives for crops currently hand-harvested. Only with this approach will horticultural crop production remain competitive and economically viable in the U.S.
Tracy L Wootten, John J. Frett, and W. Edwin Kee
In an effort to increase lima bean yields in Delaware, the documentation of lima bean plant development and the comparison of Delaware and California lima bean production was conducted. Delaware lima bean yields have averaged 1905 kg·ha-1 for the last 30 years. California averages 3923-4484 kg·ha-1. Cultivar M-15 is used by both states for production. Plant population density, plant fresh weight, and final yield was greater in California than in Delaware. Although plant populations were the same in 1992, yields remained higher in California than in Delaware. High night temperatures have an adverse affect on lima bean yields. Minimum temperatures from both states were compared. Minimum temperatures from the California planting were greater than the minimum temperatures for the late planting in Delaware.
Ed Kee, Tracy Wootten, James Adkins, and James Glancey
Proper variety selection and production practices are critical to obtaining profitable yields of mechanically harvested pickling cucumbers (Cucumis sativus L.). On the Delmarva peninsula, the tractor-mounted harvester, which utilizes the pinch-roller system for separating the pickles from the vine, was used exclusively for harvest until 1998. The pull-type forced-balance shaker machines have been introduced as an alternative harvest system. Replicated commercial-size variety trials have been conducted for four consecutive years. The trials are planted twice during the growing season, reflecting the climactic differences associated with early-season and late-season plantings. `Vlaspic' and `Lafayette' are standard varieties. Promising new varieties include `EX 1914' and `SQRP 1882'. Investigations to determine optimum plant populations and row spacing have determined that three-row beds with 60,000 plants per acre provide the highest yields and best quality fruit. Optimal operating speeds and picking reel speeds of 1.4 mph and 45 rpm, respectively, have been determined for the tractor-mounted machine. Additional design improvements have been implemented and evaluated to reduce damage. Fifty-nine replicated commercial tests evaluating the tractor-mounted harvester and the forced-balance shaker type indicate much greater harvest and throughput efficiencies are associated with the forced-balance shaker harvester, resulting in improvements between $65 and $100 per acre.