Uv-blocking Plastic Films and Nets Influence Vectors and Virus Transmission on Greenhouse Tomatoes in the Humid Tropics

Abstract

We studied the effect of UV-blocked greenhouses made from netting and plastics on the movement and pest status of three important pest of tomatoes: whiteßy (Bemisia tabaci), thrips (Ceratothripoides claratris), and aphid (Aphis gossypii). Under UV-blocked greenhouses, fewer whiteßies, aphids, and thrips entered the greenhouse compared with the ones having more UV intensity. Similarly, signiÞcantly fewer alate aphids and adult B. tabaci/leaf were counted in greenhouses with low UV intensity. Although thrips were the most abundant pest, they also were signiÞcantly less abundant in greenhouses with lower UV intensity. Consequently, signiÞcantly lower levels of leaf infestation were recorded under these greenhouse conditions. During open gates experiments, virus infection levels reached 96 Ð100% under UV nonblocking greenhouses compared with 6 Ð10% infection levels in greenhouses where UV irradiation was blocked. In addition, the appearance of virus symptoms was considerably delayed under greenhouses made from the UV-blocking roof material, although the majority of the plants tested positive for the tospovirus, capsicum chlorosis virus (CaCV; AIT isolate). The results are discussed in context of improved management of sucking insect pests of tomatoes in the humid tropics.

Visual ecology of aphids—a critical review on the role of colours in host finding

“…In the investigations on the use of mulch for protection of plants from virus diseases, three features were often stated: (1) The higher the percentage of soil covered with mulch the higher the efficiency (e.g., Adlerz and Everett 1968;Lehmhus 2001); (2) The efficiency of the mulch decreases over the growing season along with the increasing canopy of the plant (e.g., Brust 2000); (3) The comparably high costs of mulching are only economically justified in high value crops or when severe losses occur regularly due to virus diseases (e.g., Brust 2000). Finally, there is a recent report on the use of UV absorbing fabric (netting and plastics) in greenhouses for aphid control (Kumar and Poehling 2006). Under UV-blocked conditions, fewer aphids (Aphis gossypii Glover) entered the greenhouse compared with the ones having higher UV intensity.…”

Optical Manipulations: An Advance Approach for Reducing Sucking Insect Pests

“…Bionet ® provided a signi fi cant greater protection from white fl ies, B. tabaci , than standard net of the same density (Antignus et al 1998 ) . Kumar and Poehling ( 2006 ) reported that covering greenhouses with UV-blocking plastic and Bionet ® signi fi cantly reduced both attraction and invasion of white fl ies ( B. tabaci ), aphids ( A. gossypii ) and thrips ( Ceratothripoides claratus ), compared to UV-transmitting materials. Growing lettuce under UV-blocking materials decreased aphid density and the spread of aphid-transmitted viruses (Legarrea et al 2012 ) .…”

Physical Control: An Important Tool in Pest Management Programs

“…The first report on the effects of UV-blocking plastic films was (Nakagaki et al 1982), but the emphasis on modifying the characteristics of plastics for agriculture is a recent development (see review, Diaz and Fereres 2007). The effects of UV-absorbing films and nets on reducing the populations of different species of insect pests (aphids, leafhoppers, thrips, and whiteflies) have been well documented (Antignus et al 1996;Costa and Robb 1999;Costa et al 2002;Chyzik et al 2003;Kumar and Poehling 2006;Doukas and Payne 2007b;Weintraub et al 2008). Furthermore, these UV-absorbing materials have proven to be very effective in reducing the spread of insect-transmitted plant viruses (Antignus et al 1996;Diaz et al 2006).…”