The onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae) (Mart, 2005) and the leafhopper, Empoasca decipiens Paoli (Homoptera: Cicadellidae), are significant common pests on cotton crops in Turkey (Atakan et al., 2004; Atakan and Canhilal, 2004; Karut et al., 2005). Thrips species have minute, slender-bodies with rasping-sucking mouthparts (Borror et al., 1989; Olkowski et al., 1991; Mound and Kibby, 1998). They are significant plant feeder (Borror et al., 1989; Olkowski et al., 1991; Bournier, 1994; Mound and Kibby, 1998; Atakan, 2003; Mart, 2005). Therefore, plant growth, crop maturity and seed-cotton yield can decrease due to the thrips feeding (Atakan, 2003; Cook et al., 2003; Mart, 2005).

These leafhopper species are small, slender insects that disperse rapidly when disturbed (Flint, 1998) and both adults and nymphs run sideways (Flint, 1998; Mart, 2005). During their feeding process, they apparently introduce a toxin that impairs photosynthesis (Matthews, 1994). This causes the edges of leaves to curl downwards, the leaf to become yellowish and then redden, before drying out and shedding (Matthews, 1994; Mart, 2005). Severe hopper burn can severely stunt young plants and reduce yields (Matthews, 1994).

The color trap attractiveness and capture rates of thrips depend on species (Kirk, 1984) and trap color (Cho et al., 1995). The various color traps are commonly used for monitoring thrips species on many cultivated crops (Beckham, 1969; Lu, 1990; Carrizo, 2001; Liu and Chu, 2004; Atakan and Canhilal, 2004; Chen et al., 2004). The white and blue plastic and gold aluminum foils were the most attractive color traps for thrips species (Beckham, 1969). In a different study, pale blue color traps were the most attractive traps for onion thrips comparing with the white, green, yellow, gray and red ones (Lu, 1990). In addition, the blue and white color traps were more attractive for T. tabaci than orange and black color traps (Carrizo, 2001). Liu and Chu (2004) reported that the blue cup traps were more attractive for T. tabaci than the white plastic cup traps. On the other hand, the yellow sticky traps were significantly attractive for the western flower thrips on cotton crops (Atakan and Canhilal, 2004; Chen et al., 2004). A range of sticky color traps are commonly used for monitoring leafhopper species on many cultivated crops (Alverson et al., 1977; Kersting et al., 1997; Flint, 1998; Chu et al., 2000; Lessio and Alma, 2004; Raja and Arivudainambi, 2004). The yellow sticky color traps were significantly more attractive for Macrosteles fascifrons (Stål), Norvelina seminuda (Say), Paraphlepsis spp., Erythroneura spp. and Exitianus exitiosus (Uhler) species than white, green, blue and red sticky color traps (Alverson et al., 1977). Similarly, the yellow sticky color traps were significantly attractive for Circulifer haematoceps (Mulsant et Rey), Orosius orientalis (Matsumura) (Kersting et al., 1997) and E. fabae (DeGoover et al., 1998).

The purpose of this study was to evaluate the relative attraction of thrips and leafhoppers species to a range of color traps in cotton fields in Hatay province of Turkey.

A two-year study was conducted to evaluate attraction of thrips and leafhoppers species to various sticky color traps in cotton fields in Hatay province of Turkey. In the first year, 2006, two trials were conducted from 18th to 27th August and 31st August to 7th September in Kirikhan in different locations. Both trials consisted of orange, blue, yellow, green, red and white color traps. In the second year, 2007, two trials were conducted from 20th to 26th August in Kirikhan and 15th to 22nd September in Reyhanli districts. The first trial in Kirikhan district consisted of orange, blue, yellow, green and red color traps. The second trial in Reyhanli district contained green, yellow, blue and white color traps.

Index cards in the size of 13x10 cm were used as color traps in both trials in 2006 and in the first trial in 2007. The color traps were placed on 80x80 cm wooden stake crosses and separated by 2.5 cm spaces among traps. Both surfaces of each trap were coated with a thin layer of TIBTRAP®. Flat files (LEITZ®) in the sizes of 30x20 cm were used as color traps in the second trail in 2007. In this trial 130x130 cm wooden stake crosses were used to place the color traps on and they were separated by 10 cm along the horizontal. The traps` stakes were placed with a 10 m space between them within the field.

Traps were randomized in a completed design with four replications. Upon collection of sticky color traps, they were wrapped with clear plastic cling film and then transferred to the laboratory to count thrips and leafhoppers species for each evaluation date. Each of the color traps was examined under stereomicroscopic microscope in order to count the adult and nymph stages. Data were subjected to analysis of variance (ANOVA) and the means were separated by Student-Newman-Keuls (SNK) multiple comparison tests (p<0.05) using SAS software (SAS Institute, 1998).

A two-year study was carried out to evaluate attraction of thrips and leafhoppers species to various sticky color traps in the cotton fields. In the first year, the yellow sticky color traps caught significantly more thrips species in both trials than blue, orange, green, red and white color traps (F = 17.033, df = 5,18, p = 0.0001; F = 5.241, df = 5,18, p = 0.004, respectively) (Table 1). The orange color traps caught the second highest number of thrips in the first trial. However, the green color traps caught relatively low thrips numbers in both trials. The red color traps caught the lowest thrips species in the second trial.

The yellow sticky color traps were significantly attractive for leafhoppers species in both trials (F = 3.636, df = 5,18, p = 0.019; F = 3.322, df = 5,18, p = 0.027, respectively) (Table 1). The orange sticky color traps were the second attractive for leafhoppers species in both trials. Conversely, the white, green and blue sticky color traps were less attractive for leafhoppers species in the first trials. Similarly, the white sticky color traps were less attractive for leafhoppers species in the second trials.

In the second year, the blue color traps were significantly attractive for thrips species in both trials (F = 7.976, df = 4, 15, p = 0.001; F = 8.421, df = 3, 12, p = 0.003, respectively) (Table 2). The orange color traps caught the second highest number of thrips in the first trial. The white color traps were significantly more attractive than yellow and green ones in the second trial. The green color traps caught the lowest number of thrips species in both trials. Unlike the results of two trials in 2006, the yellow sticky color traps were not significantly attractive for the thrips species.

Table 1:	Number of thrips and leafhoppers caught with color traps in cotton plants in Kirikhan, Hatay in 2006
yMeans within a column not followed by the same letter are significantly different (p<0.05) by SNK

Table 2:	Number of thrips and leafhoppers caught with color traps in cotton plants in Kirikhana and Reyhanlib Hatay in 2007
yMeans within a column not followed by the same letter are significantly different (p<0.05) by SNK

The yellow sticky color traps were the most attractive for leafhoppers species in both trials (F = 10.151, df = 4, 15, p = 0.0001; F = 5.636, df = 3, 12, p = 0.012, respectively) (Table 2). The orange sticky color traps were the second attractive for both species. The green sticky color traps were the worst attractive for both species. Unlike the prior to trials, the green sticky color traps were significantly attractive for leafhoppers species. However, the blue sticky color traps were the worst attractive for leafhoppers species.

In a previous study, the yellow sticky color traps caught significantly more thrips than blue or white traps (Cho et al., 1995). The yellow sticky color traps were also significantly attractive for the avocado thrips, Scirtothrips perseae Nakahara on avocados (Hoddle et al., 2002), the basswood thrips, Thrips calcaratus Uzel, pear thrips, Taeniothrips in-cortsequem (Uzel) and native basswood thrips, Neohydatothrips tiliae on deciduous forests (Hood) (Rieske and Raffa, 2003). Furthermore, Demirel and Cranshaw (2005) reported that the neon yellow color traps were significantly more attractive for T. tabaci than yellow, blue, neon green, silver and orange color traps on brassica crops. Conversely, the blue sticky plastic cup traps were significantly attractive for onion thrips, T. tabaci in onion fields (Liu and Chu, 2004). Similarly, the blue color traps were the most attractive traps for F. occidentalis (Chu et al., 2000; Chen et al., 2004).

In the previous studies were conducted in cotton, sugarbeets, lucerne, yardlong bean and groundnut fields with nine different color traps for evaluating attraction of Empoasca spp. adults (Chu et al., 2000). The lime green, yellow and spring green sticky color traps were significantly more attractive for Empoasca spp. adults than white, rum, red, woodland green (dark green), true blue and black sticky color traps (Chu et al., 2000). The later study indicated that the yellow with red border sticky color traps were significantly attractive for Amrasca biguttula biguttula than red color traps (Raja and Arivudainambi, 2004). On the other hand, the red sticky color traps caught more S. titanus than white, yellow or blue (Lessio and Alma, 2004). Scaphoideus titanus males were significantly more attracted to red rather than to yellow and white coloured traps.

The yellow, blue and white sticky color traps were significantly attractive for thrips species in cotton crops in Hatay province of Turkey. The yellow and orange sticky color traps were significantly attractive for leafhoppers species. Therefore, the yellow, blue and white sticky color traps for thrips species and the yellow and orange sticky color traps for leafhoppers species are strongly suggested for monitoring their population densities in cotton crops.

We would like to thank for valuable assistance of Fatih Çabuk and Hatice Yildirim in these trials.