Bacterialspot is a major disease of tomato ( Solanum lycopersicum ) in Florida and worldwide ( Jones, 1991 ; Jones et al., 2004 ). The disease is associated with four species of Xanthomonas : X. euvesicatoria , X. vesicatoria , X. perforans
Field studies were conducted over three seasons to determine the effect of N and K on susceptibility of tomato to bacterial spot. A factorial randomized complete block design consisting of four rates of N (167, 334, 501, and 668 kg·ha–1) and three rates of K (334, 668, and 1335 kg·ha–1) were used. Liquid fertilizer was injected via trickle irrigation. Increasing N rates reduced disease severity, whereas the effect of increasing K was inconsistent from season to season. The concentration of N in leaf tissue showed a significant negative correlation with disease severity, whereas the concentration of Ca in leaf tissue exhibited significant positive correlation with disease severity and negative correlation with N rate during two seasons of data collection.
Bacterialspot of pumpkin, incited by X. cucurbitae (ex Bryan) Vauterin et al. (1995) [syn. Xanthomonas campestris (Pammel) Dowson pv. c ucurbitae (Bryan) Dye], has become one of the most important diseases of pumpkin [ Cucurbita pepo L. and
in tomato. Florida accounted for nearly 40% of the total U.S. gross sales ( USDA, 2010 ). Among the many diseases that affect tomato, bacterialspot is one of the most troublesome ( Bouzar et al., 1999 ; Jones et al., 2004 ; O'Garro and Charlemagne
Bacterialspot of tomato ( Solanum lycopersicum L.) was first identified in South Africa ( Doidge, 1921 ). Originally, bacterialspot was thought to be caused by only one species, Xanthomonas campestris pv. vesicatoria ( Stall et al., 1994
All possible crosses, excluding reciprocals, among 3 bacterial-spot-resistant plant introductions of pepper and the susceptible ‘Yolo Wonder’ were evaluated for resistance in the F3 along with the backcross (BC) F2s derived from backcrosses to the susceptible cultivar. PI 322719 carries a single dominant gene for resistance that is independent of the one carried by PI 163192. The resistance of PI 163189 is more complex; it is independent of the resistance of PI 322719 but may be associated with that of PI 163192. Nonsegregating, resistant families were recovered in the F3s of all crosses and backcrosses.
Bacterialspot of tomato is caused by as many as four species of Xanthomonas : X. euvesicatoria , X. vesicatoria , X. perforans , and X. gardneri ( Jones et al., 2000 , 2005 ); the former three species were previously named X. campestris
susceptibility to bacterialspot (J.W. Scott, unpublished data). Bacterialspot is also a major disease of tomato in Florida and in many regions of the world where the crop is grown in humid environments. The disease is caused by several species of Xanthomonas
Tomato (Lycopersicon esculentum Mill.) accession PI 270248 (‘Sugar’) had high levels of resistance to bacterial spot [incited by Xanthomonas campestris pv. vesicatoria (Doidge) Dye] on fruit, but foliage was susceptible. Hawaii 7998 (H7998) was highly resistant to foliar infection, but was intermediate in resistance to fruit infection. Fruit spot on hybrids between ‘Sugar’ and H7998 was usually intermediate to the parents. Occasionally, disease incidence of hybrids was not statistically different from one or both parents, but tended to resemble ‘Sugar’ more closely than H7998. There were no significant differences between reciprocal hybrids, indicating a lack of cytoplasmic inheritance. Under low disease incidence, hybrids between ‘Sugar’ and ‘Walter’ (susceptible to bacterial spot on fruit and foliage) had fruit spot incidence similar to ‘Sugar’ and significantly less than ‘Walter’. Thus, there was a high level of dominance for resistance to bacterial spot on fruit.
A `spray-inoculation seedling screening procedure was developed for detecting resistance to Xanthomonas campestris pv. vesicatoria (Doidge) Dye, causal agent of bacterial spot of tomato (Lycopersicon esculentum Mill.). Two-week-old transplants were preconditioned under 95% humidity for 16 hours before spray inoculation and then rated for bacterial spot 2 weeks later. Resistant plants could also be distinguished from susceptible genotypes using a modified bacterial speck [Pseudomonas syringae pv. tomato (Okabe) Young, Dye, and Wilkie] screening procedure (cotyledon-dip technique). When results of both screening methods were compared to field ratings from three previous seasons, significant correlations were more frequently observed for the spray-inoculation method. In Summer 1991, individual plants were evaluated by the spray-inoculation technique and then were placed in the field to determine susceptibility under field conditions. Correlations (r = 0.28 to 0.34) between spray-inoculation seedling screening ratings and field ratings, although low, were significant (P ≤ 0.0001). More than 90% of susceptible plants could be eliminated, saving labor, space, and time.