Abstracts for the 96Th Annual International Conference of The
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Abstracts Contributed Papers (Poster and Oral) ACB Orals ACB Posters Workshops Colloquia 96th Annual International Conference of the American Society for Horticultural Science Minneapolis, Minnesota USA 27–31 July 1999 The Abstracts that follow are arranged by type of session (Posters first, then Orals, Colloquia, and 42 POSTER SESSION 1 (Abstr. 001–004) Workshops). The Poster abstract numbers corre- Crop Protection spond to the Poster Board number at which the Poster will be presented. Thursday, 29 July, 1:00–2:00 p.m. To determine when a paper is to be presented, 001 check the session number in the Program Sched- Establishment of Methods in Evaluating the Susceptibility of ule or the Conference at a Glance charts. The Chinese Cabbage (Brassica campestris spp.) to Soft Rot Author presenting the paper is indicated by an Disease by Erwinia Won Jun, Soo-Seong Lee, and Jongkee Kim*; Department of Horticultural Sci- asterisk. ence, Chun-ang University, San 40-1, Nairi, Daeduck-Myun, Ansung, Kyunggi- do 456-756, Korea Three inoculation methods, including cutting of a leaf, drenching, and point inoculation, were compared in an effort to screen the susceptibility of Chinese cabbage to soft rot disease caused by Erwinia carotovora subsp. carotovora. Three- to 4-week-old seedlings from 10 lines of cabbage with 16-h-old bacterial culture were routinely used. Inoculated seedlings were kept at 25.0 ± 10.0 °C for 48 h with saturated water vapor using a plastic tunnel in a greenhouse. Sixty-day-old mature plants were produced and inoculated in a greenhouse. Severity of symp- toms, which were observed from percentage of plant infected was scored as from 1 to 9, representing resistant to susceptible, respectively. The correlation be- tween seedlings and mature plants from ten lines was evaluated among the three different inoculation methods. Point inoculation gave the most significant corre- 440 HORTSCIENCE, VOL. 34(3), JUNE 1999 lation (r = 0.843, P < 0.05) between seedlings and mature plants. A good correla- 004 tion was also observed between point inoculation of seedlings and drenching of Root Application of Potassium Silicate Reduce Feeding mature plants (r = 0.609, P < 0.05). Cutting of a leaf of seedlings was also corre- Damage to Sargent Crabapple Leaf Tissues by Adult Japa- lated with point inoculation of mature plants (r = 0.609, P < 0.05). This method nese Beetles provides the advantage of being able to keep the experimental plant alive, as only A.M. Shirazi*1 and F.D. Miller2; 1The Morton Arboretum, 4100 Route 53, Lisle, one leaf is detached. The point inoculation method is simple and relatively sensi- IL, 60532; 2University of Illinois, Countryside Extension Center 6438 Joliet Road, tive, so it could be used for large-scale screening for this bacterial soft rot dis- Countryside, IL 60525 ease. From three different evaluation assays, it was concluded that the breeding Research on silicon nutrition has shown an increase in plant disease resis- lines, C3-28, C3-29 from Cornell Univ. (Geneva, N.Y.) and the cultivar tance to powdery mildew and pythium in some species, such as roses and cu- Kweonsim319 were relatively resistant to bacterial soft rot, while the Cornell breed- cumbers. However, the role of silicon for protecting plants from other stresses ing line CC-25 and the ‘Rang-no’ cultivar were relatively susceptible. e.g., heat, drought, insects, etc., are not known. Two-year-old Sargent Crabapple Malus sargentii seedlings were subjected to 4 continuous days of 100 ml root 002 application of potassium silicate at the rate of 0, 100, 200, and 400 ppm in Aug. Effects of Hungavit® Liquid Bio-fertilizer on Leaf Chlorophyll 1998. After 3 days post-treatment, three detached leaves were placed in each of Content, Disease Incidence, and Yield of Tomato, Pepper, three petri dishes along with one adult female Japanese beetle (n = 3/concentra- and Potato tions) for 7 days. Potassium silicate at 100 ppm concentration significantly re- Nader Soltani*, George Lazarovits, and Arran Brown; Southern Crop Protection duced percent leaf tissue eaten by adult Japanese beetles. There was not any and Food Research Centre, Agriculture & Agri-Food Canada (AAFC), 1391 statistical difference between control, 200, and 400 ppm application. The ion Sandford St., London, Ontario, Canada N5V 4T3 leakage of stem tissues of 100 and 200 ppm-treated plants were significantly Hungavit® products contain extracts of earthworm castings and are marketed lower than the control and 400 ppm. These lower ion leakage effects were also by BioLife Ltd. as liquid Bio-leaf fertilizer and plant conditioner. Three experi- observed with red-osier dogwood stem tissues at 100 ppm. In a companion study mental plots were set up on the AAFC-SCPFRC research farm to evaluate fall webworm larvae were also exposed to the same above concentrations and Hungavit®UR, Hungavit®P, and a preparation containing the equivalent amount treatments. There was not a significant effect of potassium pilicate on percent leaf of N, P, K fertilizer. In Spring 1998, four replicate plots/treatment of tomato, pep- tissue eaten by fall webworm larvae, suggesting that there may be differences per, and potato were set up in a randomized block design. Each plot received the between major groups of leaf-feeding insects. Leaf and root tissue analysis for following treatments: untreated control, Hungavit®UR for tomato and pepper or Ca, K, Mg, Na, and Si will be reported. Hungavit®P for potato, and the fertilizer equivalent of Hungavit®UR or P without the organic components. Tomato and pepper plants were treated three times by foliar application at the rate of 5 L/ha using 300 L of water/ha carrier. Leaf chloro- phyll contents were measured at 2, 4, and 6 weeks after initial treatment applica- 90 POSTER SESSION 9 (Abstr. 005–015) tion. Early and total yield were determined. Tomato fruit were evaluated for symp- toms of bacterial spot, early blight, anthracnose, and blossom end rot; pepper Crop Protection fruit for bacterial spot; and potato tubers for potato scab. Both Hungavit® and its equivalent fertilizer application increased the chlorophyll readings significantly Friday, 30 July, 1:00–2:00 p.m. in at least one measurement for tomato, pepper, and potato plants. Although there were 40% to 55% fewer diseased tomato and pepper fruit in fertilizer and Hungavit ® UR treatments, this was not statistically significant from the control treatments. Fertilizer treatment also reduced scab incidence in tubers by 50%, but the overall 005 scab level was very low even in untreated plots. Hungavit® and its fertilizer equiva- Investigations Into the Cause of Gold Flecking on the Surface lent had no significant effect on the early or total yield of tomato, pepper, or of Ripe Tomato Fruit potato plants. Jeanine M. Davis*; Dept. of Horticultural Science, North Carolina State Univ., MHCREC, 2016 Fanning Bridge Rd., Fletcher, NC 28732 003 In recent years there has been an increase in the incidence of “gold flecking,” Epidemiology and Control of Pepper Stip which develops on the surface of ripe tomato fruit. Gold flecking looks like a light Richard Smith*1, Robert Mullen2, and Tim Hartz3; 1Monterey and 2San Joaquin sprinkling of gold on the skin of the fruit. There are no lesions and the interior of Counties, Calif.; 3Dept. of Vegetable Crops, University of California, Davis, CA the fruit is not affected. Usually, gold flecking is barely noticeable. In 1998, how- 95616 ever, gold flecking was severe enough in some cases to cause economic losses. Pepper stip is a physiological disorder manifested as gray-brown to greenish It has been suggested that gold flecking is due to use of the insecticide Asana or spots occurring on the fruit of bell, pimento, Anaheim, and other types of pep- it may be a genetic disorder. The objective here was to determine if gold flecking pers, most noticeably on red fruit that mature under fall conditions. Most hybrid is caused by Asana and/or is cultivar-dependent. Treatments consisted of three bell cultivars are resistant to the malady; the problem is most severe for pepper cultivars (Mountain Fresh, Celebrity, and Mountain Pride) and four insecticides growers reliant on less-expensive, open-pollinated cultivars. In 1995, we initi- (Asana XL, Karate 1 EC, Thiodan 50 WP, and a water control). There were two ated studies to evaluate the possible link between mineral nutrition and this dis- plantings. Only red fruit was harvested. For both plantings, there was more gold order. Two susceptible open-pollinated cultivars and two resistant hybrid culti- flecking in the control than any of the insecticide treatments. There were no differ- vars were grown in randomized plots at seven sites. Significant correlations were ences among the insecticides. For the early planting, ‘Mountain Fresh’ had more seen between the levels of potassium (r = 0.59) and calcium ( r = –0.37) in whole gold fleck than the other cultivars. In the late planting, there were no differences leaves and the incidence of stip (P = 0.05). The stip-resistant cultivars also main- between cultivars. This study demonstrates that Asana was not responsible for tained less total nitrogen in the whole leaves than susceptible cultivars (P = 0.05). gold flecking and actually reduced it compared to the control. These results also In 1996 and 1997, we undertook field studies to evaluate the effects of varying suggest that insects may play a role in gold flecking. calcium and nitrogen application rates. Inconsistent results were observed with calcium applications. Moderate reductions in stip incidence was observed at some 006 sites and no reduction at others following foliar calcium applications. Nitrogen Effects of Chitosan on Growth and Rot of Soybean Sprouts nutrition had no effect on stip severity.