YIELD AND ECONOMICS OF INTERVENTION WITH PEACH-TREE SHORT LIFE DISEASE

Fumigation, rootstocks, and time of pruning of peaches [Prunus persica (L.) Batsch] were studied to determine if the cost of soil fumigation would be recovered when replanting peach trees on a peach tree short life (PTSL) site. Incidence of PTSL, yield, and economic return were determined over 3 yr. Treatments were fumigation with 98% methyl bromide or no fumigation, 'Lovell' or 'Nemaguard' rootstocks, and pruning in December or March. Pruning effects were inconsistent from year to year and did not affect the 3-yr-cumulative yield. Fumigation increased yield per tree and decreased tree loss due to PTSL. Significant interactions between fumigation and rootstocks indicated that fumigation increased yield per tree more with Lovell than with Nemaguard rootstocks. Increased yield and decreased mortality following fumigation increased economic return by 31% over the nonfumigated treatment. Soil fumigation increased yields sufficiently on a PTSL site to justify the practice economically.