Porter L D, Dasgupta N, Johnson D A
Department of Plant, Soil and Entomological Sciences, University of Idaho, Aberdeen Research and Extension Center, Aberdeen 83210-0870.
Department of Statistics, Washington State University, Pullman 99164-3144.
Plant Dis. 2005 Feb;89(2):146-152. doi: 10.1094/PD-89-0146.
The effects of tuber depth, soil type, and soil moisture on potato tuber infection due to Phytophthora infestans were assessed under greenhouse conditions in soil contained in large pots. Healthy tubers were used to assess infection and were either hand buried in soil at specific depths or naturally formed from potato plants growing in the soil. A spore suspension of P. infestans was chilled to induce zoospore formation and a suspension of resulting zoospores and sporangia were applied to the soil. Soil depth at which tubers became infected was used to determine the extent of spore movement in the soils. Tuber infection significantly decreased with increasing soil depth. Most infected tubers were found at the surface of soil; infection was rare on tubers at 5 cm or deeper in the soil. Amount of tuber infection varied among soil types. Significantly less tuber infection occurred in a Shano silt loam than in medium and fine sands. Only tubers on the soil surface were infected in the Shano silt loam. Depth in soil at which tubers became infected did not differ significantly among Quincy fine sand, Quincy loamy fine sand, and Quincy medium sand. Increased soil moisture did not significantly increase the soil depth at which tuber infection occurred, regardless of the soil type.
在温室条件下，于大花盆中的土壤里，评估了块茎深度、土壤类型和土壤湿度对马铃薯块茎因致病疫霉感染的影响。使用健康块茎评估感染情况，这些块茎要么人工埋于特定深度的土壤中，要么由生长在土壤中的马铃薯植株自然形成。将致病疫霉的孢子悬浮液冷却以诱导游动孢子形成，然后将产生的游动孢子和孢子囊悬浮液施用于土壤。块茎被感染时的土壤深度用于确定孢子在土壤中的移动范围。随着土壤深度增加，块茎感染显著减少。大多数受感染的块茎位于土壤表面；在土壤中5厘米或更深位置的块茎很少被感染。块茎感染量因土壤类型而异。在沙诺粉质壤土中发生的块茎感染明显少于中砂和细砂。在沙诺粉质壤土中，只有土壤表面的块茎被感染。在昆西细砂、昆西壤质细砂和昆西中砂中，块茎被感染时的土壤深度没有显著差异。无论土壤类型如何，土壤湿度增加均未显著增加块茎感染发生时的土壤深度。
