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United States Department of Agriculture

Agricultural Research Service

Title: Integrated management of tomato diseases in open field-grown tomatoes in Southern Italy

Authors
item Fanigliulo, A. - UNIVERSITA BASILICATA,ITA
item Comes, S. - UNIVERSITA BASILICATA,ITA
item Pacella, R. - UNIVERSITA BASILICATA, IT
item Momol, M. - UNIVERSITY OF FLORIDA
item Olson, S. - UNIVERSITY OF FLORIDA
item Reitz, Stuart
item Crescenzi, A. - UNIVERSITA BASILICATA,ITA

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 8, 2007
Publication Date: January 1, 2009
Citation: Fanigliulo, A., Comes, S., Pacella, R., Momol, M.T., Olson, S.M., Reitz, S.R., Crescenzi, A. 2009. Integrated management of tomato diseases in open field-grown tomatoes in Southern Italy. Acta Horticulturae. 808:387-392.

Interpretive Summary: Tomato spotted wilt virus (TSWV) is one of a growing list of Tospoviruses adversely affecting field tomato crops worldwide. In addition to TSWV, other serious threats for tomato production in Italy are the aphid transmitted Cucumber Mosaic Virus (CMV) and Potato virus Y (PVY), both with necrogenic and non necrogenic variants. Epidemics caused by TSWV, PVY and CMV occur regularly in southern Italy, were hundreds of millions of industry tomato plants are grown every year. Insecticides applied on a calendar schedule for insect control are not effective in preventing the diseases progress, because virus transmission can occur before insects (thrips and aphids) are killed by insecticides. Scientists with USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, the Università degli Studi della Basilicata (Italy) and the University of Florida have conducted field trials to develop more effective management programs for these insect-vectored pathogens. Two approaches that we studied were the use of ultraviolet reflective mulches to repel pest insects and acibenzolar-S-methyl, a non-toxic chemical that boosts the plants’ natural immune response system. The UV reflective mulch alone was effective in reducing disease incidence both for aphids and thrips transmitted viruses. A synergic effect of Actigard with UVRM was observed against the three viruses. These tactics are leading to more effective management programs for these devasting insect-vectored diseases and are proving useful in reducing synthetic insecticide use in tomato production.

Technical Abstract: Tomato spotted wilt virus (TSWV) is one of a growing list of Tospoviruses adversely affecting field tomato crops worldwide. The only known means of virus transmission is via vectors belonging to a few species of thrips. The most important vectors in Italian conditions are Frankliniella occidentalis and Thrips tabaci. Only the first instar larvae can acquire the virus from an infected plant. After acquisition, the virus replicates in the vector and the viruliferous thrips is capable of transmission for the duration of its life. Apart from TSWV, other serious threats for tomato production in Italy are the aphid transmitted Cucumber Mosaic Virus (CMV) and Potato virus Y (PVY), both with necrogenic and non necrogenic variants. Epidemics caused by TSWV, PVY and CMV occur regularly in southern Italy, were hundreds of millions of industry tomato plants are grown every year. Insecticides applied on a calendar schedule for insect control are not effective in preventing the diseases progress, because virus transmission can occur before insects (thrips and aphids) are killed by insecticides. A field experiment was conducted during summer of 2005 and 2006 in the main tomato growing area of the Basilicata region, Lavello (PZ), to determine the separate and integrated effects of UV-reflective mulch (UVRM), Acibenzolar-S-methyl (Actigard) and insecticides for the management of vectors and viruses on tomato. TSW disease pressure was great during 2005 summer but very low in 2006. Disease incidence was measured as percentage of TSWV infected plants and with the percentage of ELISA positive plants for the three viruses. Aphid populations were evaluated by counting the number of aphids on sampled tomato shoots on one third of the plants on each plot. Yield was evaluated weighing marketable product from one third of the plants on each plot. Statistical analysis (analysis of variance) was performed using the SYSTAT 9 Software. The UVRM alone was effective in reducing disease incidence both for aphids and thrips transmitted viruses. A synergic effect of Actigard with UVRM was observed against the three viruses. The use of the insecticides alone resulted in a reduction of disease incidence of the three viruses on UVRM, and in the reduction of CMV and PVY disease alone in the black mulch covered and uncovered plots. The combination of UV-reflective mulch, acibenzolar-S-methyl, and insecticides was very effective in reducing tomato spotted wilt incidence in tomato. The UV-reflective mulch was very effective in delaying and reducing colonization of aphids and subsequent virus incidence. There was no significant difference in the yield between UVRM and black mulch treatments. By contrast, a strong yield reduction was observed in the uncovered treatment, probably due to the effect of weed competition with tomato.

Last Modified: 11/27/2014
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