Replant Disease
Pythium spp., Phytophthora spp., Rhizoctonia spp., Fusarium spp., and Pratyle...
62 host plants
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When you replant apples, pears, cherries, or grapes on ground where the same species grew previously, vigorous young trees may suddenly stall in early summer after leafing out normally in spring. Affected trees produce little or no new shoot growth, their leaves stay small and pale, and the root system fails to generate many new feeder roots while existing roots deteriorate. This complex condition develops over the first few years after transplanting and reflects the accumulated stress from multiple soil pathogens and environmental factors interacting together.
The reality here is that replant disease stems from a dark alliance: fungi, oomycetes, and nematodes all persist in orchard soil, and their combined effect paralyzes young root development far more effectively than any single pathogen alone. Acidic soil compounds the problem by reducing nutrient availability and increasing toxic element concentration. Your best defense is prevention: rotate out of pome or stone fruit for 5 to 8 years, adjust pH to 6.5 or higher with lime, or if replanting is unavoidable, establish trees in the old drive rows rather than the old tree rows to minimize disease pressure.
Quick Reference
Management
Recently-vacated orchard soil; previously replanted fruit-tree sites; susceptible rootstock; waterlogged or poorly drained soils; nematode-infested soils; dense plantings with root zone overlap
Cultural Controls
- Avoid by not planting Prunus sp. on ground where old Prunus or pome fruit orchards have recently been removed.
- Rotations of 5 to 8 years are recommended in the absence of other tactics.
- Correct soil physical characteristics that are detrimental to growing cherry trees.
- Adjust soil pH to 6.5 to 7 using agricultural lime and adding organic matter, such as mulch or compost, to improve the buffering capacity of the soil.
- Plant a non-woody cover crop for 3-5 years before planting a new orchard can reduce disease pressure.
- Mixtures of brassicas, grasses and/or legumes are the most commonly planted cover crops but may require irrigation, especially during establishment in dry areas, and fertilizer applications.