Occurrence of Peach Tree Short Life on a Field Site with No History of Peach Production

Abstract

Table 1. Soil population density (1985 to 1989) of Criconemella xenoplax (Cx) on Nemaguard peach planted in Dec. 1985 on a site not recently planted with peaches (n = 12). Peach tree short life (PTSL) usually is associated with poor management practices and the continuous presence of the ring nematode [Criconemella xenoplax (Raski) Luc & Raski = Mesocriconema xenoplax (Raski) Loof & de Grisse]. Bacterial canker (Pseudomonas syringae pv. syringae van Hall), cold injury, or both are responsible for the sudden springtime collapse of peach trees associated with PTSL in the southeastern United States (Brittain and Miller, 1978). However, C. xenoplax (Cx) clearly has been identified as the primary biotic factor essential for PTSL to occur (Nyczepir, 1990). Although generally associated with old orchard sites, PTSL can be induced in virgin peach soil in field microplots by inoculation with ring nematode (Nyczepir, 1990). Our objective was to determine if PTSL could occur on land not planted with peaches for ≥75 years. The field site was a loamy sand (86% sand, 10% silt, 4% clay; 1.54% organic matter) located at the Southeastern Fruit and Tree Nut Research Laboratory, Byron, Ga. The site, recently cleared of ≈75-year-old pecan trees, had no known history of peach production. Soil pH was 6.0, so preplant liming was not required. Preplant nematode soil samples revealed no Cx in July 1985. Twenty-four rooted cuttings of Nemaguard were planted at 6 × 6 m in Dec. 1985. Each of 12 cuttings had been inoculated with 10,000 adult and juvenile Cx per 3700 cm soil in Apr. 1985, while the remaining 12 cuttings received nematode-free water extract from the culture medium and served as controls (Nyczepir, 1990). Each nematode-inoculated tree also received 16,000 Cx in the planting hole. Treatments were replicated 12 times and arranged in a randomized complete-block design. Trees were cultured as recommended by the Georgia Cooperative Extension Service. Nematode populations were monitored beneath the canopy of each tree in