Mature-green and mature-red tomato (Lycopersicon esculentum Mill.) fruit were harvested from spring- and fall-grown plants infested with sweet potato whitefly (SPWF; Bemisia tabaci Gennadins). The mature-green fruit were either ripened at 20 to 22C or cold-stored at 10 to 13C for 3 weeks and then were allowed to ripen at 20 to 22C. There was no significant difference in the appearance of either external or internal tomato irregular ripening (TIR) symptoms between the two storage–ripening regimes or in the appearance of internal TIR symptoms among the two storage regimes and vine-ripened tomatoes. Thus, removing the tomatoes from the SPWF during ripening does not reduce TIR symptoms. About half of the mature-green tomatoes, ripened with or without cold storage (10 to 13C), developed no external TIR symptoms, but about half of these tomatoes had internal TIR symptoms. About one-third of the tomatoes developed external symptoms during ripening, but these symptoms disappeared after ripening was complete. A high percentage (71%) of these tomatoes with external symptoms also had internal symptoms. The remaining tomatoes developed external TIR that did not disappear, and almost all of these tomatoes had internal symptoms. These data suggest that culling tomatoes that develop external TIR during ripening will reduce but not eliminate tomatoes with internal TIR from the fresh-fruit market.
Charles A. Powell and Peter J. Stoffella
James D. McCreight and William M. Wintermantel
, 1965 ; Tzanetakis et al., 2003 ; Wintermantel, 2004 ). Sweet potato whitefly, Bemisia tabaci (Gennadius), biotype B (SPWF-B) adversely affects yield and quality of a wide range of vegetable and agronomic crops worldwide directly through feeding
Aliya Momotaz, Jay W. Scott, and David J. Schuster
IV trichomes, while 10 plants were selected as susceptible (S) based on their low adult mortality, high numbers of eggs deposited, and 0 to very few type IV trichomes ( Table 1 ). Table 1. Sweet potato whitefly (SPWF) egg deposition, SPWF
Charles A. Powell and Peter J. Stoffella
Tian-Ye Chen, Chang-chi Chu, Thomas J. Henneberry, and Kai Umeda
Insects in a commercial poinsettia (Euphorbia pulcherrima) greenhouse were monitored with yellow sticky card (YC) traps and YC equipped with 530-nm lime green light-emitting diodes (LED-YC) traps from 3 June to 25 Nov. 2002. Pest insects were: dark-winged fungus gnat (Bradysia coprophila), sweet potato whitefly (Bemisia tabaci) biotype B (= B. argentifolii), western flower thrips (Frankliniella occidentalis) and leafhopper (Empoasca sp.). Natural enemies were: minute pirate bug (Orius tristicolor), parasitic wasps (Hymenoptera), and rove beetles (Staphylinidae). Over the 24 weeks of the experiment, LED-YC traps captured more dark-winged fungus gnats, sweet potato whiteflies, leafhoppers, and rove beetles compared with YC traps. Capture of western flower thrips, minute pirate bugs, and parasitic wasps were not significantly increased on the YC traps equipped with LEDs. The results indicate that the LED-YC traps attract three major pest insects in poinsettia greenhouses and do not catch more beneficial, minute pirate bugs and parasitic wasps, but may catch significant number of rove beetles. The results suggest that LED-YC traps may be useful to monitor and reduce pest populations in greenhouses.
Michael Brownbridge, Bruce L. Parker, and Margaret Skinner
Western flower thrips (WFT), green peach aphid (GPA) and sweet potato whitefly (SPWF) are major pests of the greenhouse industry. Chemical control of these pests is not desirable. Alternative approaches to pest management need to be developed.
Entomopathogenic fungi hold great promise as sustainable biological control options. A broad range of indigenous fungal isolates have been screened for activity vs. WFT and GPA. Strains of Metarhizium anisopliae, Beauveria bassiana and Verticillium lecanii have been shown to be particularly effective. Plant and soil trials vs. WFT are now underway to permit selection of the best strains for further development. To date, assays vs. SPWF indicate that strains of Paecilomyces farinosus and B. bassiana are the most pathogenic.
L.P. Brandenberger and R.P. Wiedenfeld
The squash leaf curl virus (SLCV), transmitted by the sweet potato whitefly (Bemesia tabaci biotype B), is widespread on fall-planted watermelon in the Rio Grande Valley and Coastal Bend areas of south Texas. The objective of the study was to evaluate colored mulches for their effects on whitefly populations, virus incidence, and watermelon yield. Eleven polyethylene films were included as treatments in both a spring and fall study and were replicated five times in a randomized block design. Plastic mulches caused substantial improvement in melon yields (40%) in the spring crop, similar to responses obtained in other studies on cantaloupes. Fall yield increases due to the use of mulches did not occur. Whitefly populations were much lower in 1996 than they have been in previous years, therefore this was not an adequate test of its effects on whitefly behavior. Even so, there were indications in the fall crop that the use of plastic mulch tended to result in lower whitefly numbers. No evidence was found of any difference between the various mulch materials regarding whitefly counts.
James D. McCreight, Hsing-Yeh Liu, and Thomas A. Turini
Cucurbit leaf crumple geminivirus (CuLCrV) is transmitted by sweet-potato whitefly (Bemisia tabaci) biotype B (SPWF-B) and occurs on cucurbits in Arizona, California, Texas, and Mexico. This virus is identical to Cucurbit leaf curl virus, and their symptoms are similar to Squash leaf curl virus on squash (Cucurbita sp.) and Melonleaf curl virus on melon (Cucumis melo L.). Melon has been reported to be either susceptible to CuLCrV, or to have the ability to recover from infection. Twenty-three melon cultigens were inoculated with CuLCrV in greenhouse tests using SPWF-B. Eighteen of the cultigens tested were highly susceptible to CuLCrV (≥60% infected plants) and generally exhibited pronounced CuLCrV symptoms: `Amarillo', `Edisto 47', `Esteem', `Fuyu 3', `Impac', `Moscatel Grande', `Negro', `Perlita', PI 234607, PI 236355, PI 414723, `PMR 5', `Seminole', `Sol Dorado', `Sol Real', `Top Mark', `Vedrantais', and WMR 29. Five cultigens were resistant to CuLCrV (<40% infected plants that exhibited restricted, mild symptoms): MR-1, PI 124111, PI 124112, PI 179901, and PI 313970. Symptoms abated with time in both groups although infected plants remained positive for the virus. Ten of the cultigens (`Edisto 47', `Fuyu 3', `Impac', MR-1, PI 124112, PI 313970, PI 414723, `PMR 5', `Top Mark', and WMR 29) were included in field tests in 2003 and 2004 that were naturally infected with CuLCrV. With the exception of PI 414723, the greenhouse and field data were consistent for reaction to CuLCrV.
-growing greenhouse were monitored with yellow sticky card traps (YC) and YC equipped with 530-nm lime-green light-emitting diodes (LED-YC) by Chen et al. (p. 337). Compared with YC, LED-YC captured more of three major pests (dark-winged fungus gnat, sweet potato
) primarily has relied on insecticidal controls targeting the vector, sweet potato whitefly (SPW). However, resistance of SPW to insecticides, increased length of the growing season, and asymptomatic hosts of TYLCV have increased the need for wider use of