Protection of hop against the primary infection with false powdery mildew

Abstract

Goal. To determine effective ways of protection of hop seedlings against primary infection with false powdery mildew. Methods. Field — a survey of hop plantations, accounting and study of the dynamics of primary infection with false powdery mildew on hop seedlings, assessment of plant damage, determining the effectiveness of biological and chemical preparations; laboratory — analysis of damaged and affected hop plants; weight — determination of the saved harvest; morphophysiological — determination of biometric parameters of plants; mathematical and statistical — assessment of the reliability of the results, the establishment of correlations and calculations of economic efficiency of advanced hop plant protection systems. Results. It is established that on hop seedlings the most effective way of protection against primary infection of the false powdery mildew is watering of hop queens with a mixture of chemical and biological fungicides: Valis M, v.g. + Hetomik, p.; Quadris SC, k.s. + Hetomik, p. and Valis M, v.g. + Agat 25 K, t.ps., the efficiency of which was 90.9–92.0% and exceeded the standard by 1.5–2.6%, while the number of spike-shaped shoots decreased to 1.2–1.4 pcs/bush. The varieties Zagrava and Slovyanka were more stable with a degree of damage of 40% and intensive development of the disease 30% (5 points), and 66.5 and 46% (7 points), respectively. Conclusions. The use of tank mixtures of chemical and biological fungicides to protect hop plantations against primary infection with false powdery mildew allows controlling at a high level (up to 92%) the development of the pathogen, minimizing the appearance of spike-like shoots on seedlings.