Preplant Soil Compost or Fumigation, Rootstock Disease Resistance or Tolerance, and Previous Tree or Grass Rows as Management Factors in Apple Replant Disease.
Project Leader: Ian A. Merwin, Assoc. Professor, Dept. of Horticulture, 118 Plant Science, Cornell University, Ithaca, NY, 14853
Dr. George S. Abawi, Prof. of Plant Pathology, 630 North St., N.Y. State Agr. Exp. Station, Geneva, NY, 14456
Dr. Janice Thies, Dept. Crop & Soil Science, Cornell Univ. Ithaca, NY, 14853
Dr. Angelika Rumberger, Post-Doctoral Assoc. Dept. Horticulture, Cornell Univ. Ithaca, NY
Ms. Shengrui Yao, Graduate Student Research Assistant, Dept. of Horticulture, Cornell University, Ithaca, NY, 14853
Ms. Michelle Leinfelder, Graduate Student Research Assistant, Dept. of Horticulture, Cornell University, Ithaca, NY, 14853
Mr. Richard Reisinger, Research Farm Manager, Dept. of Horticulture, Ithaca, NY
Type of grant: Cultural methods; sanitation; physical controls
Project location: Cornell Orchards, Dryden Road, Ithaca, NY. The research site is a commercially managed research orchard, and results from this project will be immediately applicable throughout the Northeast US, and elsewhere nationally where orchard replant problems occur.
When orchards are replanted to maintain productivity, apple replant disease (ARD) often causes major problems. Soil fumigants sometimes control ARD, but biological and cultural alternatives are needed. This project evaluated disease-resistant apple rootstocks and preplant soil treatments with compost and a fumigant as methods to improve apple tree growth and productivity in a replanted orchard. After the first year of observations, tree growth on M9 was weak, and unimproved by any preplant soil treatment. For the other rootstocks, preplant soil fumigation or compost had little effect on tree growth, but location of replants where the previous tree rows had been situated substantially reduced growth of trees on M26, G16 and M7 rootstocks compared with the old grass lanes. In contrast, trees on CG210 (a.k.a. CG6210) and CG30 rootstocks grew more strongly in all preplant soil treatments, and equally well in the old grass lanes and tree rows. Soil fertility (P, K, Ca, Cu, B, pH, and organic matter content) increased substantially in compost amended soil, but this did not improve tree growth on most of the rootstocks. Populations of both beneficial (free-living saprophytic) and parasitic root-lesion (Pratylenchus penetrans) nematodes were greater in the old grass lane soil compared to old tree row locations, suggesting that the lesion nematode is not an important factor in ARD at this site. Based upon one years observations in this multiyear study, it appears that CG30 and CG210 rootstocks may be resistant or tolerant to soil-borne pathogens causing ARD at this site.