In July 2001, a study was established in a field with a 30-year history of perennial strawberry production to examine effects on replant disorder of 12 different species of preplant cover crops, soil fumigation (methyl bromide plus chloropicrin), and fallow management. In May 2002, strawberries (`Jewel') were planted into pots containing soils with the incorporated cover crops, grown for 1 year, and then fruited. Strawberry yields in 2003 were highest in pots containing indiangrass (Sorghastrum avenaceum) and brown mustard (Brassica juncea) -incorporated soils, resulting in 32% and 28%, respectively, higher yield than plants in pots containing untreated, bare fallow soil. Yield was lowest in fumigated soil or soil incorporated with sunnhemp (Crotolaria juncea), having 19% and 10% less yield than the fallow treatment, respectively. In Aug. 1999, a complementary study was established in a field with a 7-year history of continuous perennial strawberry production to examine the effects of single species and multiple species rotations on replant disorder, bacterial populations, and fungal pathogens over 2 fruiting years. Cover crop treatments included various monocultures and sequences of perennial alfalfa (Medicago sativa), brown mustard, kale (B. oleracea `Winterbor'), sweet corn (Zea mays `Saccharata'), rye (Secale cereale), hairy vetch (Vicia villosa), marigold (Tagetes patula `Nema-gone'), oats (Avena sativa `Newdak'), and sudangrass (Sorghum bicolor × S. sudanese). These rotations were compared with the effects of fumigation using methyl bromide with chloropicrin (99:1), continuous strawberry, and bare fallow. Symptoms of replant disorder developed in the continuous strawberry plots within a few months of planting. Plants in the fumigation treatment produced greater fruit yield than all other treatments in 2003, 139% more than plants from the continuous strawberry treatment. Strawberry plants grown in the kale/sweet corn/rye treatment had consistently high yield, and both the hairy vetch/marigold/rye and the oats/sudangrass/rye treatments led to marked improvement over the continuous strawberry treatment. Plants from the brown mustard treatment also were more vigorous and productive than plants from the continuous strawberry treatment during 2002 despite having relatively low foliar biomass and a relatively high level of fungal infection on strawberry plant roots. In the field, symptoms of replant disorder were best overcome by fumigation with methyl bromide or multiple species rotations, particularly that of kale followed by sweet corn and rye. Although Rhizoctonia levels were associated with poor root health, general fungal and bacterial root infection rates were not consistently associated with the presence of visible symptoms of replant disorder nor with strawberry plant growth and productivity.
Ann Toren Seigies and Marvin Pritts
Dorcas K. Isutsa, Ian A. Merwin and Bill B. Brodie
Orchard replant disorder (ORD) is a widespread soilborne disease complex that causes stunting and poor establishment of replanted fruit trees. Chemical and cultural control of ORD provide effective, but short-term, control. More-sustainable strategies would involve ORD-resistant rootstocks not yet identified in apple. We tested `Bemali', G11, G13, G30, G65, G189, G210, and G707 clones from the apple rootstock breeding program at Geneva, N.Y., for their response to ORD in a composite soil collected from New York orchards with known replant problems. Clones were tested in the greenhouse in steam-pasteurized (PS), or naturally infested field soils (FS) with about 900 Pratylenchus penetrans and 150 Xiphinema americanum per pot. Plant dry mass, height, root necrosis, and nematode populations were determined after 60 days under optimal growing conditions. Stunting, reduced plant dry mass, and root necrosis were more severe in FS than in PS for most of the clones (P ≤ 5%), but G30 and G210 were substantially more tolerant to replant disorder than smaller ones, but this toleratnce might not be sustained in fields with greater or more prolonged nematode infestations. There is sufficient variation in apple rootstock resistance or tolerance to ORD to suggest that genetic resistance may be identified and developed for better management of orchard replant problems.
A.P. Nyczepir, B.W. Wood and C.C. Reilly
Pecan [Carya illinoinensis (Wangenh.) K. Koch] trees exhibit nickel (Ni) deficiency in certain orchard situations. The symptoms are manifest as either mouse-ear or replant disorder and in certain situations are associated with nematode parasitism. A field microplot study of pecan seedlings treated with either Meloidogyne partityla or Criconemoides xenoplax or both found that parasitism by M. partityla can result in enhancement in the severity of mouse-ear symptoms and a reduction in foliar Ni concentration. The Ni threshold for triggering morphological symptoms in young developing foliage was between 0.265 and 0.862 μg·g–1 dry weight, while the threshold for rosetting was between 0.007 and 0.064 μg·g–1 dw. Results indicate that parasitism by M. partityla is a contributing factor to the induction of Ni deficiency in pecan and raises the possibility that nematode parasitism and Ni nutrition can be contributing factors to many plant maladies.
G.H. Neilsen, J. Beulah, E.J. Hoguel and R.S. Utkhede
Apple seedling height after 7 weeks of growth in greenhouse pots was compared with total first year shoot growth of `McIntosh' or `Delicious' apple trees [Malus domestica (Borkh.)] on M.26 rootstock for eight orchards and five soil treatments. The apple trees were replanted in old orchard sites with the same treatments applied in the planting hole as were tested in the greenhouse. The pot test successfully predicted treatments that increased first year shoot growth in 23 of 30 opportunities. However, a less precise relationship (R2 = 0.38) existed between total first year shoot growth (Y) of `Summerland Red McIntosh' on M.26 rootstock and seedling height (X).
G.H. Neilsen and J. Yorston
In an apple (Malus domestica Borkh.) orchard with a severe replant problem, tree size was increased by the 2nd year and number of fruit by the 3rd year by treating the planting hole soil with formalin or mancozeb plus monoammonium phosphate (MAP) fertilizer. Growth increases were evident each year for 4 years only for the MAP + formalin treatment. In a second orchard, with a less severe replant problem, planting-hole treatment with formalin or dazomet + MAP increased tree size by year 2. Number of fruit in year 2 was increased by formalin and mancozeb + MAP treatments, although this effect persisted in year 3 only for mancozeb + MAP. Leaf P concentrations were increased to high values in the first year by MAP fertilization but declined in subsequent years. Leaf Mn concentration also increased in one orchard, a consequence of fertilizer-induced acidification of planting hole soil and Mn uptake from the fungicide mancozeb. Chemical names used: tetrahydro-3,5-dimethyl-2 H -l,3,5-thiadiazine-2-thione (dazomet); 37% aqueous solution formaldehyde (formalin); Zn, Mn ethylene dithiocarbamate (mancozeb).
G.H. Neilsen, J. Beulah, E.J. Hogue and R. Utkhede
The effects of various nonfumigant planting-hole treatments on growth and yield of apple (Malus domestics Borkh.) trees were measured during the first 3 years after planting. Eight orchards diagnosed as having a replant problem were monitored. First-year shoot growth, the number of blossoms in the second year (inmost orchards), and first-year trunk cross-sectional area increment (TCAI) in 50% of test orchards were increased by monoammonium phosphate (MAP) fertilizer+ peat, MAP+ mancozeb, or MAP + peat + a bacterial antagonist. By the end of year 3, TCAI generally was not affected by treatments, but treatments resulted in more blossoms by the third season in two of seven orchards that blossomed in the second season. Cumulative yield after 3 years increased significantly in only three orchards, with the best treatment, MAP+ peat, resulting in cost recovery in only one orchard. Inadequate K or Cu nutrition may have reduced growth in some of the orchards, which were characterized by a wide range in yields, independent of planting-hole treatment.
William C. Johnson, Phil L. Forsline, Herb S. Aldwinckle, William C. Johnson, Phil L. Forsline, H. Todd Holleran, Terence L. Robinson and John J. Norelli
In 1998, the USDA-ARS and Cornell Univ. instituted a cooperative agreement that mobilized the resources for a jointly managed apple rootstock breeding and evaluation program. The program is a successor to the Cornell rootstock breeding program, formerly managed by Emeritus Professor of Horticultural Sciences James N. Cummins. The agreement broadens the scope of the program from a focus on regional concerns to address the constraints of all the U.S. apple production areas. In the future, the breeding program will continue to develop precocious and productive disease-resistant rootstock varieties with a range of vigor from fully dwarfing to near standard size, but there will be a renewed emphasis on nursery propagability, lodging resistance, tolerance to extreme temperatures, resistance to the soil pathogens of the sub-temperate regions of the U.S., and tolerance to apple replant disorder. The program draws on the expertise available at the Geneva campus through cooperation with plant pathologists, horticulturists, geneticists, biotechnologists, and the curator of the national apple germplasm repository. More than 1000 genotypes of apple rootstocks are currently under evaluation, and four fire blight- (Erwinia amylovora) resistant cultivars have been recently released from the program. As a service to U.S. apple producers, rootstock cultivars from other breeding programs will also be evaluated for productivity, size control, and tolerance to a range of biotic and abiotic stress events. The project will serve as an information source on all commercially available apple rootstock genotypes for nurseries and growers.
Maria Gannett, Marvin P. Pritts and Johannes Lehmann
increase strawberry plant density and yield ( Portz and Nonnecke, 2011 ). Decreases in yield when a farmer does not rotate the field are collectively known as strawberry replant disorder. Another factor that may play a role in strawberry replant disorder
Elsa Sánchez, William J. Lamont Jr and Michael D. Orzolek
reduce replant disorders in strawberry HortScience 41 1303 1308 U.S. Department of Agriculture 2007 The National Organic Program. Program standards 5 Mar. 2007 < www.ams.usda.gov/nop/NOP/standards.html >. Walz, E. 1999 Final results of the third biennial
Sally M. Schneider and Bradley D. Hanson
-plant fumigation of soil Phytopathology 92 1337 1343 Eayre, C.G. Sims, J.J. Ohr, H.D. Mackey, B. 2000 Evaluation of methyl iodide for control of peach replant disorder Plant Dis. 84 1177 1179 Flegg, F.F.M. Hooper, D.F. 1970 Laboratory methods for work with plant