Plant Growth Regulators (GA3 and CCC) and Silverleaf Whitefly Effects on the Induction of Tomato Irregular Ripening in Dwarf Cherry Tomato

Abstract

<jats:p>External and internal tomato irregular ripening (TIR) symptoms have been associated with the feeding of silverleaf whitefly (SLW), <jats:italic>Bemisia argentifolii</jats:italic> Bellows and Perring. Soil drench application of gibberellic acid (GA<jats:sub>3</jats:sub>) (100 ppm, Trial 1 and 2) and cycocel (CCC) (2000 ppm, Trial 1; 1000 ppm, Trial 2) were applied to dwarf cherry tomato (<jats:italic>Lycopersicon esculentum</jats:italic>) in the presence and absence of SLW to mimic the TIR disorder induced by the SLW. Application of GA<jats:sub>3</jats:sub> induced external and internal TIR symptoms similar to the SLW-induced disorder in `Florida Petite'. There were essentially no TIR symptoms in fruit treated with CCC, an inhibitor of GA biosynthesis. In Trial 1, internal white tissue in GA<jats:sub>3</jats:sub>, SLW, and CCC treatments was expressed in 97%, 95%, and 4% of the total fruit, respectively. Incidence of external TIR symptom was highest (56%) in the GA<jats:sub>3</jats:sub> plus SLW treatment. In Trial 2, GA<jats:sub>3</jats:sub> application in the presence (83%) or absence (85%) of SLW resulted in the highest incidence of fruit with internal white tissue. External TIR symptoms induced by GA<jats:sub>3</jats:sub> in the presence and absence of SLW were reduced with CCC application. These results suggest that the TIR disorder in tomato is induced by the SLW may be a GA<jats:sub>3</jats:sub>-regulated disorder.</jats:p>