Zhang Shouan, Vallad Gary E, White Thomas L, Huang Cheng-Hua
Tropical Research and Education Center, University of Florida, IFAS, Homestead 33031.
Gulf Coast Research and Education Center, University of Florida, IFAS, Wimauma 33598.
Plant Dis. 2011 Apr;95(4):461-468. doi: 10.1094/PDIS-07-10-0521.
Powdery mildew, caused by Podosphaera xanthii (syn. Sphaerotheca fuliginea auct. p.p.), is a serious and frequently occurring disease of cucurbits worldwide. Efficacy of four microbial products (i.e., Actinovate AG, Companion, BU EXP 1216C, and BU EXP 1216S), which contain microbes as the active ingredient, were evaluated on summer squash and cantaloupe against powdery mildew when applied alone or in alternation with a half-rate of conventional fungicide under greenhouse and field conditions. In greenhouse experiments, the product BU EXP 1216S significantly (P < 0.05) reduced the disease severity by nearly 70% relative to the water control. The level of control achieved was not significantly different from that obtained with Procure 480SC (triflumizole), the half-rate of conventional fungicide treatment, in two of four greenhouse experiments. Compared with the untreated water control, BU EXP 1216C and BU EXP 1216S, when applied alternately with Procure 480SC, consistently promoted plant growth measured by plant height, stem caliper, total fresh weight, and chlorophyll content in the leaves. The degree of increase was 11.6 and 11.3% in plant height, 15.6 and 19.8% in stem caliper, 25 and 40.7% in chlorophyll content, and 164 and 250% in total fresh weight, respectively. Alternating applications of these products with Procure 480SC resulted in significantly less powdery mildew disease than in the water control. In the first field trial on summer squash, all products applied individually or in alternation with Procure 480SC significantly reduced the severity of powdery mildew at the early stage (60 days after planting [DAP]) of disease development. Moreover, these alternating treatments resulted in significantly better control than with Procure 480SC alone at the late assessment stage (88 DAP). The products in alternation with Procure 480SC had a level of disease reduction equivalent to Procure 480SC alone on cantaloupe and significantly reduced disease severity in comparison with the water control. Compared with applying the microbial products alone, alternating applications of these products with Procure 480SC significantly reduced disease severity on cantaloupe and improved the marketable fruit number and weight. The data from our studies suggest that these microbial products could be effectively incorporated into disease management programs. In particular, these microbial products could be integrated into the management of powdery mildew on summer squash and cantaloupe in Florida by alternating their application with low rates of conventional fungicides, potentially reducing the development of fungicide resistance in the pathogen population.
白粉病由黄色单囊壳白粉菌（同义词：瓜白粉菌部分权威鉴定）引起，是全球葫芦科作物上一种严重且频发的病害。对四种以微生物为活性成分的微生物产品（即Actinovate AG、Companion、BU EXP 1216C和BU EXP 1216S）进行了评估，在温室和田间条件下，将它们单独使用或与半量常规杀菌剂交替使用，以防治西葫芦和甜瓜上的白粉病。在温室试验中，产品BU EXP 1216S相对于清水对照显著（P < 0.05）降低了病害严重程度近70%。在四个温室试验中的两个试验里，所达到的防治水平与使用半量常规杀菌剂处理的Procure 480SC（三氟菌唑）没有显著差异。与未处理的清水对照相比，当BU EXP 1216C和BU EXP 1216S与Procure 480SC交替使用时，通过株高、茎粗、总鲜重和叶片叶绿素含量衡量，持续促进了植株生长。株高增加幅度分别为11.6%和11.3%，茎粗增加幅度分别为15.6%和19.8%，叶绿素含量增加幅度分别为25%和40.7%，总鲜重增加幅度分别为164%和250%。这些产品与Procure 480SC交替使用导致白粉病病害明显少于清水对照。在西葫芦的首次田间试验中，所有单独使用或与Procure 480SC交替使用的产品在病害发展早期（种植后60天[DAP]）显著降低了白粉病的严重程度。此外，在后期评估阶段（88 DAP），这些交替处理的防治效果明显优于单独使用Procure 480SC。与Procure 480SC交替使用的产品在甜瓜上的病害减轻程度与单独使用Procure 480SC相当，且与清水对照相比显著降低了病害严重程度。与单独使用微生物产品相比，这些产品与Procure 480SC交替使用显著降低了甜瓜上的病害严重程度，并提高了可销售果实的数量和重量。我们研究的数据表明，这些微生物产品可以有效地纳入病害管理方案。特别是，通过将这些微生物产品与低剂量常规杀菌剂交替使用，它们可以纳入佛罗里达州西葫芦和甜瓜白粉病的管理中，有可能减少病原菌群体中抗药性的发展。
