Tomato Diseases To Spotter For
Entomology too Plant Pathology, Oklahoma State University 127 Noble Research Center, Stillwater, OK 74078 405.744.5527 Vol. 17, No. xix http://entoplp.okstate.edu/pddl/pdidl 6/22/2018
Tomato Disease Update
John Damicone, OSU Extension Plant Pathologist
Department of Entomology too Plant Pathology Oklahoma State University
See https://apps.dasnr.okstate.edu/SSL/entoplp.okstate.edu/pddl/2018/PA%2017-19.pdf
Tomato diseases are rearing their ugly heads every bit fruit are ready too merely about rainfall too a lot of humid conditions has returned. After visiting merely about marketplace farms end calendar week too putting merely about other string on plants inwards my garden, this is what I saw: Bacterial spot too speck These diseases are rattling similar inwards that they campaign defoliation of plants from the bottom upwardly too campaign fruit spotting. They are hard to course of report inwards the champaign every bit their symptoms are rattling similar too may laissez passer on off together. They are likewise hard to course of report from Septoria leafage spot, a fungal disease.
Entomology too Plant Pathology, Oklahoma State University 127 Noble Research Center, Stillwa
See https://apps.dasnr.okstate.edu/SSL/entoplp.okstate.edu/pddl/2018/PA%2017-19.pdf
Symptoms get every bit dark, mostly circular, greasy appearing, water-soaked spots on lower leaves (Fig. 1). Spots rarely run past times close 1/8 inch inwards diameter. Leaf spots caused past times bacterial spot too speck are smaller than early on blight, merely about other fungal affliction too lack the concentric rings associated amongst early on blight. Spots may or may non live surrounded past times a xanthous halo, which is to a greater extent than typical of bacterial speck. When spots run numerous, leaves may develop varying levels of yellowing, shrivel, too die. The diseases progresses from the bottom of the institute upward. Fruit spots caused past times bacterial spot too speck are dissimilar too their symptoms are useful for differentiating the 2 diseases.
Fruit spots caused past times bacterial speck are to a greater extent than often than non pivot caput size (Fig. 2) piece fruit spots caused past times bacterial spot are larger, reaching upwardly to ¼ inch inwards diameter too a scabby appearance (Fig. 3). In my observations, fruit spots to a greater extent than often than non laissez passer on off infrequently inwards our climate too the most harm from these diseases are from the institute defoliation which reduces institute productivity too longevity. Bacterial spot too speck are mutual where crop rotation is express past times infinite constraints. This is a mutual work inwards residential gardens too pocket-sized marketplace farms. Generally 3-year rotations away from tomatoes too peppers are necessary to impact levels of the diseases. Other practices are management of infested crop residual too command of volunteer tomatoes because the affliction is seed borne. Ultimately because at that spot are no resistant varieties, spray programs amongst copper- based fungicides are required to minimize bacterial spot too speck.
In situations where at that spot is dubiousness inwards whether tomato plant diseases are fungal or bacterial, it is best to apply a tank mixture of a copper too chlorothalonil (e.g. Bravo, Daconil, or Ortho Garden Disease Control).
Consult the OSU Extension Agent’s Handbook (Circular E-832) for to a greater extent than data too a listing of registered abode too commercial formulations of copper too chlorothalonil.
Figure 1: Foliar symptoms of bacterial spot and/or speck
Figure 2: Bacterial spot on tomato
Bacterial canker Bacterial canker is typically a work inwards commercial champaign too greenhouse tomato plant production. It’s a rattling destructive affliction because it tin kill entire plants. Symptoms initially look every bit a foliar leafage scorch commencement at the leafage edges. The leading edges of the scorch look page light-green inwards colouring (Fig. 4).
Petioles of affected leaves develop pocket-sized blister-like cankers from which the affliction gets its cite (Fig. 5).
Fruit on affected plants develop white “bird’s midpoint spots” which are highly feature of the affliction (Fig. 6). Control of bacterial canker should focus on excluding the pathogen from tomato plant operations too sanitation mensurate to confine its carryover from twelvemonth to year. The pathogen survives on crop residue, tomato plant stakes, transplant containers, too greenhouse surfaces. It is of import to eliminate its carryover from twelvemonth to year. Bleach solutions (10%) are effective inwards cleaning upwardly canker infestations on stakes too surfaces.
Figure 4: Bacterial canker on tomato plant foliage. F Figure 5: Blisters or cankers on petioles caused past times bacterial canker.
Figure 6: Fruit spots caused past times bacterial canker. Tomato Spotted Wilt Virus Tomato Spotted Wilt Virus (TWSV) has been a sporadic work on peanuts too tomatoes inwards Oklahoma for many years. It has never accomplish severe levels hither compared to S Texas or the Southeastern U.S.A. We’ve had a tomato plant sample exam positive for this affliction inwards the Plant Disease too Insect Diagnostic laboratory this twelvemonth too I receive got an infected institute inwards my garden. This is non a major outbreak past times whatever way but proceed an midpoint out for it.
Symptoms on tomatoes look every bit bronzing or stippling on the upper leaves too petioles (Fig. 7). Occasionally band spots are visible inwards the leaves. Symptoms look on private branches or entire plants.
Eventually end shoots of affected plants plough xanthous or dark-brown too eventually wilt too conk (Fig. 8).
TSWV is spread past times thrips feeding on infected plants every bit juveniles. The thrips run infective when they molt into adults. Current query indicates that thrips transmit the virus inwards the belatedly autumn too wintertime to weedy hosts which thence serve every bit local sources of the virus for thrips the next spring. Planting tomato plant varieties amongst resistance to the affliction inwards the best management strategy. It’s likely best to cull out infected plants shortly later on symptoms look thence that they don’t serve every bit sources of the virus for thrips.
Figure 7: Bronzing of tomato plant foliage caused past times tomato plant spotted wilt virus. Figure 8: Wilt too decease of tomato plant foliage caused tomato plant spotted wilt virus