Submitted to: Horticulture Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2009
Publication Date: 4/1/2009
Citation: McKenzie, C.L., Albano, J.P. 2009. The effect of time of sweetpotato whitefly infestation on plant nutrition and development of tomato irregular ripening disorder. Horticulture Technology. 19(2):353-359. Interpretive Summary: Tomato irregular ripening (TIR) disorder is associated with Bemisia tabaci biotype B feeding and is characterized by incomplete ripening of longitudinal sections of fruit. Our objective was to determine the effect of time of whitefly infestation on plant nutrition and the development of tomato irregular ripening disorder. Healthy tomato plants were introduced to whitefly infestations at different developmental stages of plant growth (control, 5-7 true leaf, flower, green fruit, and breaking red fruit). Nutrition, plant and whitefly parameters were monitored over time and fruit was rated for tomato irregular ripening disorder at final harvest. We found infestations of the B-biotype whitefly can cause substantial losses in tomato crop production due to tomato irregular ripening at all stages of tomato plant growth. Control of whitefly must be maintained up to tomato crop harvest, as we found that tomato irregular ripening can be induced by this pest within two weeks of harvest with plants having mean total nymph counts for this time period as low as 8.8 nymphs per 50 mm2. Plant nutrition was also affected by B-biotype whitefly with infested plants, in general, having greater foliar nutrient levels at all stages of plant growth than non-infested plants.
Technical Abstract: Tomato irregular ripening (TIR) disorder is associated with Bemisia tabaci biotype B feeding and is characterized by incomplete ripening of longitudinal sections of fruit. Our objective was to determine the effect of time of whitefly infestation on plant nutrition and the development of tomato irregular ripening (TIR) disorder. Healthy tomato plants were introduced to whitefly infestations at different developmental stages of plant growth: 1) 5-7 true leaf, 2) flower, 3) green fruit, 4) breaking red fruit and compared to uninfested control plants of the same age. Plants were fertilized every 7 to 14 days. Plant nutrition was monitored over time between the uninfested control and the longest infestation interval (5-7 leaf) and between all infestation intervals (5) at harvest. Whitefly (egg, nymph, adult) and plant parameters (height, width, number of leaves, flowers and fruit per plant) were taken every 10 to 14 days after whitefly infestation. All fruit (99%) produced by tomato plants infested with whitefly at stages 1 and 2 (78 and 56 days of whitefly exposure, respectively) developed TIR with fruit exhibiting both internal and external symptoms. Plants infested at stage 3 (35 days of whitefly exposure) had 79 to 80% of the fruit develop TIR. Surprisingly, 58% of fruit from plants infested at stage 4 (14 days of whitefly exposure) also developed the disorder indicating that tomatoes may need to be protected from whitefly until harvest to avoid this disorder. Seed germination was not affected by TIR. In general, regardless of time of infestation, plants infested with whitefly had higher foliar nutrient levels than control plants (i.e., never infested with whitefly) at final harvest.