Agronomical management influence on the spatiotemporal progress of strawberry dry wilt in Michoacan, Mexico

The spatiotemporal distribution of strawberry wilt, caused by Fusarium oxysporum, Phytophthora sp., Pythium aphanidermatum and Rhizoctonia fragariae, was studied with the aim to establish the effect of some technological components of the strawberry crop cv. Camarosa (Fragaria x ananassa Duch.) and sustain their use in an integral management of the disease. Epidemics were characterized in two cropping seasons at three localities in Valle de Zamora, Michoacan, Mexico, in commercial plantations with plastic mulch and drip irrigation (A+G), and non-mulch and gravity irrigation (T) on a 100 m2 area per site. Temporal parameters were contrasting between both management techniques. A+G plantations had significantly lower final incidence (Yf =12.8±5.6%) than T (22.5±5.9%) (p=0.05) and were consistent with estimators of area of curve (ABCPEa and ABCPEe). The range of epidemic intensity reduction induced by A+G was 22.21 to 76.7% day, which was reflected in lower apparent infection rates (b-1=0.0015-0.0027, R2=0.92-0.99). Lloyd’s Index of Patchiness and Morisita Index (1.01 to 1.17) indicated a slightly aggregated dispersion pattern. Autocorrelation and geostatistical analysis confirmed lower aggregates in A+G (up to 5 plants) vs. T (8 plants), but an apparent higher mobility of inoculum in A+G up to 6.5 m. Plastic mulch and drip irrigation are proposed as technological components of an eventual integrated management program of dry wilt in Michoacan.   Key words: Epidemiology, plastic mulch, drip irrigation, strawberry dry wilt.