Fourth International Bemisia Workshop International Whitefly Genomics Workshop
Control Strategies for Bemisia tabaci (Genn.) Biotype B and Other Insect Vectors in Tomato Lycopersicum esculentum (Mill.)
1 Departamento de Fitossanidade – Faculdade de Ciências Agrárias e Veterinárias – Campus de Jaboticabal/SP, Brasil. Correspondence: aboicajr@fcav.unesp.br
2 Departamento de Proteção de Plantas – Faculdade de Ciências Agrárias da Unesp – Campus de Botucatu/SP, Brasil
3 Pontifícia Universidade Católica – PUC, Campinas/SP, Brasil
Tomato (Lycopersicum esculentum, Mill.) is considered to be a high risk crop due to infestation of many pests, in fields intended for the production of fruits to be consumed in natura or processed. Because insect pests attack tomato plants during their entire cycle, it is very challenging to grow tomatoes under field conditions. To control early pests (thrips, aphids and whiteflies) many insecticide sprayings are required, sometimes every 3 days throughout the plant cycle, often combining two or more products. However, this procedure has resulted in the selection of resistant insect populations and environmental problems. In this study, we compare insect vector control techniques in tomato cultivars. Two experiments were carried out. The first was conducted in Cafelândia/SP with the cultivars AP 529 and H 108, to compare the following control techniques: 1) conventional, with application of carbofuran 50 G (soil) and sprayings with acephate 750 BR, metamidophos 600, thiacloroprid, imidacloprid 700 GRDA, chlorfenapyr, fenitrothion 500 CE, carbaryl 480 SC and abamectina 18 CE; 2) integrated Pest Management (IPM) with application of carbofuran 50 G, and adopting the action threshold for vector pests to spray imidacloprid 700GRDA, triflunuron 250 PM, lufenuron CE and abamectina 18 CE; 3) IPM and carbofuran 50 G, adopting the action threshold to spray 0.5% Neem oil extract (1.2% azadirachtin); 4) IPM adopting the action threshold to spray 0.5% Neem; 5) untreated control. The second experiment was conducted in Guarantã/SP with the cultivars AP 529 and Malinta, comparing the techniques: 1) conventional, with application of carbofuran 50 G and sprayings as described before; 2) IPM adopting the action threshold to spray 0.5% Neem; 3) sorghum barrier with no spraying; 4) maize barrier with no spraying; 5) IPM adopting the action threshold to spray 0.5% Neem plus sorghum barrier; 6) IPM adopting the action threshold to spray 0.5% Neem plus maize barrier; 7) control. Control treatments were conducted with the same cultivars without insecticide or Neem applications. The ‘conventional technique’ consisted of the same approach used by farmers, in which insecticides are sprayed according to a pre-set schedule, every three to six days. The mean number of adults of Bemisia tabaci (Genn.) biotype B, Frankliniella schultzei (Trybom) and Myzus persicae (Sulz.), the total vector count per plant, the rate of plants with virus symptoms and tomato yield (t.ha−1) were determined. Data were submitted to an ANOVA and F test through the software ESTAT and means were compared by Tukey test at 5% of probability. No difference was observed for cultivars in the first experiment in terms of pest infestation. However, whiteflies were observed in higher levels than aphids or thrips in both cultivars. The conventional control technique resulted in the lowest number of adults per plant (1.46, 0.79 and 0.86 whiteflies, thrips and aphids, respectively), followed by IPM with carbofuran 50 G plus insecticide sprayings, and IPM with Neem oil extract and carbofuran 50 G. The conventional control also resulted in the highest productivity (52.24 t.ha−1), followed by IPM with carbofuran 50 G (48.45 t.ha−1) and IPM with Neem and carbofuran 50 G (45.96 t.ha−1). Compared to the untreated control, these techniques increased tomato productivity in 79.52, 66.50, 57.94, and 56.67%, respectively. The second experiment showed no difference between cultivars in total vectors (whiteflies, aphids and thrips), however the whitefly population was the highest. Conventional control allowed the highest reduction in white fly population followed by IPM with Neem oil extract and maize barrier, with 1.33 and 2.31 adults per plant, respectively. The same was observed for total vectors, with means of 2.46 and 3.87 per plant for conventional control and IPM with Neem oil extract and maize barrier. The productivity was inversely proportional to the mean number of insects. The conventional technique showed the lowest infestation rate and the highest productivity (62.72 t ha−1). The sorghum barrier was not effective in controlling insect vectors, being statistically similar to the untreated control. Productivity increases of 71.10, 41.13, 4.70, 40.45 and 48.18% were reached with IPM with Neem, sorghum barrier without sprayings, maize barrier without sprayings, IPM with Neem and sorghum barrier, and IPM with Neem and maize barrier, respectively. The whitefly infestation is higher in comparison to the other virus vectors, and the conventional control is the most efficient, followed by IPM with Neem oil extract and carbofuran, and IPM with Neem oil extract and maize barrier, which are all promising to control these pests.