Replant disease

Sewell GWF (1981) Effects of Pythium species on the growth of apple and their possible role in replant disease. Annals Appl Biol 97 31... 

Braun, PG. The combination of Cylindrocarpon lucidum and Pythium irregulare as a possible cause of apple replant disease in Nova Scotia. Can J Plant Pathol 1991 13 291-297. 

Braun, P.G. Effects of Cylindrocarpon and Pythium species on apple seedlings and potential role in apple replant disease. Can J Plant Pathol 1995 17 336-341. 

Isutsa, D.K., Merwin, I.A. Malus germplasm varies in resistance or tolerance to apple replant disease in a mixture of New York orchard soils. Hortsdence 2000 35 262-268. 

Mazzola, M. Elucidation of the microbial complex having a causal role in the development of apple replant disease in Washington. Phytopathology 1998 88 930-938. 

Szabo, K., Wittenmayer, L. Plant specific root exudations as possible cause for specific replant diseases in Rosaceen. J Appl Bot 2000 74 191-197. 

The time-honored method of controlling insect-borne virus diseases is by breeding resistant varieties. This has been practical in annual crops, but is hopelessly slow in tree crops, where it may take 20 years or more to test a new variety. What is needed desperately is some sort of treatment which will control the virus, probably a systemic treatment, as the virus works within the plant cells. This is not a new idea and work has been done along this line by many workers. A sense of urgency is inevitable, however, when 500 to 600 acres of citrus can be wiped out completely in 3 to 5 years time, followed by an expensive replanting job and a wait of 5 to 6 years to get back into production. This is the outstanding problem at the present time and may need years to answer. 

When replacing perennial vegetable plants, or dividing and replanting (see p.l93), do not replant on the same site. Check for pests and diseases on perennial crops, especially those such as nine-star broccoli that are related to other vegetables. Pests and diseases that become established on perennial crops can be a source of infection for other plants. 

Stunted growth may be caused by viruses or strawberry red stele disease. Remove the plants do not replant on the same site with strawberries or raspberries. 

In gardens or allotments, tubers obtained from the grocery store could be used for planting (unlike potatoes), because Jerusalem artichoke is relatively pest- and disease-free. Tubers can also be carefully harvested and saved, stored indoors (e.g., in the dark at 0°C and 90 to 95% relative humidity), for replanting in the spring. 

GREEN FALLOW. If there are replanting problems (poor tree growth due to soil exhaustion), a green fallow for a few years is advisable. Complete destruction of the carriers of viral diseases and other microorganisms (e.g. actinomycetes as a cause of soil exhaustion) is not always possible with a green fallow (Riidel, 1989). 

Branches wilt. Cause Verticilliiim wilt. Parts of trees infected with this fungal disease may wilt suddenly or produee leaves that are yellow or smaller than normal. Cut and destroy or dispose of affected branches. Trees may recover if you provide extra water and fertilizer to promote strong, new, healthy growth. Remove severely infected trees don t replant another maple in the same spot. 

Tree declines stunted pale leaves no new growth. Cause Root rot. Root rot can be caused by overwatering or by poorly drained soil, but the disease may take years to develop. There is no cure. Replant in well-drained soil or on a raised mound of soil. Grande and Martin are rootstocks resistant to this problem. 

Root rot causes reddish black streaks on the roots plants are stunted and yellow. Cool, wet soil encourages this fungal disease. Destroy wilted plants. Replant with fresh seed in well-drained, warm soil. Soak seed in compost tea before planting. 

Plant wilts suddenly. Cause Bacterial wilt. This disease causes a soft rot at the base of the stem, killing plants quickly. Remove and destroy infected plants. Do not replant cosmos in that area. 

Stems blacken at base leaves wilt plant falls over. Cause Crown or root rots. Both fungi and bacteria cause crown and root rot of delphiniums. Plants may wilt suddenly or yellow and wilt slowly. Stems and roots may turn black mold may appear. Poorly drained, overly wet soil promotes rot choose well-drained sites and add organic matter to improve drainage. Avoid injury to crowns when digging near plants keep winter mulch away from crowns. Remove and destroy infected plants wash tools used around diseased plants. Solarize the soil before replanting. 

Plant wilts stems rot at soil level. Cause Fungal or bacterial rots. Pinks are susceptible to various diseases that cause plants to wilt suddenly or to rot at or below the soil surface. This is especially true of plants growing in wet or poorly drained soil or in crowded conditions. Prevent problems by planting in well-drained sites, and avoid overwatering and overcrowding keep mulch away from stem bases. Remove and destroy infected plants do not compost diseased materials. If the probiem is serious, solarize the soil before replanting a site. 

Leaves yellow plant dies early. Cause Dry rot. Other symptoms of this fungal disease include dry, brown or black, corky spots on corms and husk coverings. You may see black fungal growth spots on decayed leaf bases. Plants may turn yellow and die prematurely. Choose corms carefully to avoid infected specimens. Destroy infected plants. Do not replant in same area. Replant only in well-drained soil. 

Leaves mottled yellow and distorted flowers small and faded. Cause Fusarium yellows. This soilborne fungal disease is first seen as bending and curling of leaves and stems foliage yellows and dies, starting with the oldest leaves. On corms small reddish brown lesions enlarge and darken entire corms may become hard, dry, and mummified. Immediately destroy infected corms. Do not replant corms in same... 

Leaves with reddish hrown spots corms with pale to hrown spots. Cause Scab. This bacterial disease also causes brown spots on blossoms plants rot at the base and fall over. Spots on corms turn dark brown with sunken centers and scabby margins. Dig and destroy infested plants do not replant corms in infested soil. 

Pierce s disease, a bacterial disease common in the South, is spread by leafhoppers. Infected vines typically show scorched, dried leaves in midsummer, wilted dried fruit, and eventual death of the vine. There is no cure for this disease. Dig up infected plants and replant with disease-free stock. Muscadine grapes are resistant to Pierce s disease, as are the American grape cultivars Champanel , Herbemont , and Lenoir . 

Leaves with water-soaked spots foliage and flowers blacken. C ause Bacterial blight. Infected plants turn brown and lose leaves girdled stems die. Dig and destroy infected plants and surrounding soil. Solarize soil before replanting with disease-free seed water early in the day so leaves dry quickly. 

Tree stunted or dying. Cause Plum leaf scale. This disease is common in the Southeast. There is no cure. Dig up infected plants and replant with a resistant cultivar such as AU-Rosa or AU-Amber . 

Cause Crumbly berry virus. This disease is incurable. Dig out and destroy infected plants and replant at a new site with virus-free (also called virus-indexed) plants. 

Cause Mosaic virus. This disease is transmitted by aphids and appears only on black or purple raspberries. Red raspberries may carry the virus but will show no symptoms. Infected purple or black raspberries eventually become stunted and develop small, misshapen leaves with green blisters. The only control is to dig up infected plants and replant with virus-free (also called virus-indexed) stock. Also avoid planting raspberries in sites near wild or old, neglected raspberries. Since red raspberries may carry the disease, keep plantings of black and purple raspberries separate from red raspberries. Royalty purple raspberry is less susceptible to mosaic than other purple raspberries because it is seldom infested with the species of aphid that transmits the disease. 

Seed from open-pollinated varieties of com can be saved for replanting, but hybrid seed tends to revert to the character of the original inbred lines after the initial expression of optimum traits in the hybrid generation. The hybrid is proprietary in character as the particular inbred lines can be kept secret. The farmer is motivated to use the proprietary hybrid over purebred varieties because of the relative advantages of the hybrid in terms of such qualities as superior yield and increased disease resistance. Kloppenburg... 

The virulent strain of V, albo-atrum will remain in the soil for 3-4 years after an initial infection and chemical disinfection of the soil has had only limited success. The disease can be eradicated from the soil by growing non-susceptible plants such as grasses but it is essential that certain weeds are eliminated. Groundsel, for example, is a symptomless carrier of the disease. In the Weald, where there is a higher chance of reinfection, most gardens that have been attacked by progressive wilt have been replanted with wilt-tolerant varieties. This is not the practice elsewhere because the tolerant varieties could become symptomless carriers of the disease. 

Plants showing symptoms of nettlehead should be grubbed and the land left fallow for two years (or eighteen months if treated with dichloropropene) before being replanted with stocks certified as being free of the disease. 

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