Elmer Wade H, Ferrandino Francis J
Plant Pathologist.
Associate Agricultural Scientist, The Connecticut Agricultural Experiment Station, P.O. Box 1106, New Haven, CT 06504.
Plant Dis. 2009 May;93(5):485-489. doi: 10.1094/PDIS-93-5-0485.
The role of earthworms in plant disease has received little attention. To address whether earthworms would affect the severity of Verticillium wilt of eggplant (Solanum melongena) in the field, we grew eggplants in experimental field plots that were naturally infested with Verticillium dahliae in 2005, 2006, and 2007. Three earthworm treatments were compared: (i) no treatment (untreated control), (ii) earthworm populations reduced via chemical eradicants (carbaryl or hot mustard) (reduced treatment), and (iii) earthworm populations increased by addition of adult Canadian nightcrawlers (Lumbricus terrestris, 11 earthworms per m) (augmented treatment). Compared to the untreated control, the estimates of the area under the disease progress curve (AUDPC) were reduced while estimates of the canopy growth curve (CGC) and the final plant weights were increased in plots augmented with earthworms in all 3 years. In 2 out of 3 years, eggplant yield (weight and number of fruit) was increased in plots augmented with earthworms. When a carbaryl drench was used to reduce earthworm numbers, the treatment resulted in plants with more disease than in the untreated controls in 2005. However, in 2005 and 2006, carbaryl-treated plants had larger CGC values and higher yield than in the untreated controls and were not significantly different from the augmented plots. When a hot mustard extraction procedure was used to reduce earthworm densities in 2007, plant growth, yield, and disease variables did not differ from the untreated control. Although the effects of reducing earthworms were variable and difficult to explain, our findings suggest that augmenting earthworm populations can suppress Verticillium wilt of eggplant, and strategies that increase earthworm numbers may contribute to disease suppression.
蚯蚓在植物病害中的作用很少受到关注。为了研究蚯蚓是否会影响田间茄子（茄属）黄萎病的严重程度，我们于2005年、2006年和2007年在自然感染大丽轮枝菌的试验田种植茄子。比较了三种蚯蚓处理方式：（i）不处理（未处理对照），（ii）通过化学药剂（西维因或辣根）减少蚯蚓数量（减少处理），以及（iii）添加成年加拿大夜蚯蚓（陆正蚓，每平方米11条蚯蚓）增加蚯蚓数量（增加处理）。与未处理对照相比，在所有3年中，蚯蚓增加处理的地块中，病害进展曲线下面积（AUDPC）估计值降低，而冠层生长曲线（CGC）估计值和最终植株重量增加。在3年中的2年里，蚯蚓增加处理的地块中茄子产量（果实重量和数量）增加。当使用西维因灌根减少蚯蚓数量时，2005年该处理导致植株病害比未处理对照更多。然而，在2005年和2006年，西维因处理的植株CGC值更大且产量高于未处理对照，与蚯蚓增加处理的地块无显著差异。2007年当使用辣根提取程序降低蚯蚓密度时，植株生长、产量和病害变量与未处理对照无差异。虽然减少蚯蚓数量的效果多变且难以解释，但我们的研究结果表明增加蚯蚓数量可以抑制茄子黄萎病，增加蚯蚓数量的策略可能有助于病害抑制。
