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Violet LED light enhances the recruitment of a thrip predator in open fields

View Article: PubMed Central - PubMed

ABSTRACT

The predatory bug Orius sauteri is an indigenous natural enemy of thrips and whiteflies in Asian countries. To put these bugs to practical use in pest management, methods to attract and retain the bugs in agricultural fields are needed. We previously showed that violet light (405 nm) attracts O. sauteri selectively. Many thrips and whiteflies are attracted to UV or green light. In this study, we examined the effect of violet-LED illumination on O. sauteri in pesticide-free eggplant (Solanum melongena L.) cultivation. In three cultivation trials, the density of O. sauteri on eggplant leaves was consistently higher in the illuminated plots; at least twice that of the non-illuminated plots. Simultaneously, the density of thrips declined markedly to less than half that of the non-illuminated plots. We identified three positive effects of violet light including an “immediate-effect” on predator attraction, a “persistent-effect” on predator reproduction, and a “secondary-effect” on the food web structure. Our results showed that illumination with violet light provides a powerful tool for integrated pest management. This is the first report on the use of illumination to manipulate the behavior of natural enemies.

No MeSH data available.


The densities of Orius sauteri and thrips in plots with and without LED.Mean numbers of O. sauteri and thrips captured per week after turning on the LED light source in Trial 3. Vertical bars indicate standard error (n = 12). Statistical analysis was by the Mann-Whitney U-test. * and ** indicate statistical significance at p < 0.05 and p < 0.01, respectively.
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f4: The densities of Orius sauteri and thrips in plots with and without LED.Mean numbers of O. sauteri and thrips captured per week after turning on the LED light source in Trial 3. Vertical bars indicate standard error (n = 12). Statistical analysis was by the Mann-Whitney U-test. * and ** indicate statistical significance at p < 0.05 and p < 0.01, respectively.

Mentions: In Trial 3, we reduced the number of rope LED lights by two-thirds, to examine the effects of violet light. During the experimental period, the total numbers of O. sauteri and thrips captured in the illuminated plots were 47 and 16, respectively, while those captured in the non-illuminated plot were 21 and 43, respectively. The total numbers of O. sauteri captured in the illuminated plots were 2.7 times greater than in the non-illuminated plots. The total numbers of thrips in the illuminated plots were reduced by 70% of the value for the non-illuminated plots. The mean numbers of O. sauteri and thrips captured per week after turning on LED light are shown in Fig. 4. The numbers of O. sauteri and thrips captured weekly in the illuminated plots were 2.75 ± 0.79 and 0.67 ± 0.32 (mean ± SE, n = 12), respectively, and 0.92 ± 0.40 and 2.33 ± 0.46, respectively, in the non-illuminated plots. From these results, a greater number of O. sauteri (p < 0.05) and a smaller number of thrips (p < 0.01) were always captured in the illuminated plots. These results showed that the effect of violet was valid even if the number of LED lights was reduced by two-thirds.


Violet LED light enhances the recruitment of a thrip predator in open fields
The densities of Orius sauteri and thrips in plots with and without LED.Mean numbers of O. sauteri and thrips captured per week after turning on the LED light source in Trial 3. Vertical bars indicate standard error (n = 12). Statistical analysis was by the Mann-Whitney U-test. * and ** indicate statistical significance at p < 0.05 and p < 0.01, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015028&req=5

f4: The densities of Orius sauteri and thrips in plots with and without LED.Mean numbers of O. sauteri and thrips captured per week after turning on the LED light source in Trial 3. Vertical bars indicate standard error (n = 12). Statistical analysis was by the Mann-Whitney U-test. * and ** indicate statistical significance at p < 0.05 and p < 0.01, respectively.
Mentions: In Trial 3, we reduced the number of rope LED lights by two-thirds, to examine the effects of violet light. During the experimental period, the total numbers of O. sauteri and thrips captured in the illuminated plots were 47 and 16, respectively, while those captured in the non-illuminated plot were 21 and 43, respectively. The total numbers of O. sauteri captured in the illuminated plots were 2.7 times greater than in the non-illuminated plots. The total numbers of thrips in the illuminated plots were reduced by 70% of the value for the non-illuminated plots. The mean numbers of O. sauteri and thrips captured per week after turning on LED light are shown in Fig. 4. The numbers of O. sauteri and thrips captured weekly in the illuminated plots were 2.75 ± 0.79 and 0.67 ± 0.32 (mean ± SE, n = 12), respectively, and 0.92 ± 0.40 and 2.33 ± 0.46, respectively, in the non-illuminated plots. From these results, a greater number of O. sauteri (p < 0.05) and a smaller number of thrips (p < 0.01) were always captured in the illuminated plots. These results showed that the effect of violet was valid even if the number of LED lights was reduced by two-thirds.

View Article: PubMed Central - PubMed

ABSTRACT

The predatory bug Orius sauteri is an indigenous natural enemy of thrips and whiteflies in Asian countries. To put these bugs to practical use in pest management, methods to attract and retain the bugs in agricultural fields are needed. We previously showed that violet light (405&thinsp;nm) attracts O. sauteri selectively. Many thrips and whiteflies are attracted to UV or green light. In this study, we examined the effect of violet-LED illumination on O. sauteri in pesticide-free eggplant (Solanum melongena L.) cultivation. In three cultivation trials, the density of O. sauteri on eggplant leaves was consistently higher in the illuminated plots; at least twice that of the non-illuminated plots. Simultaneously, the density of thrips declined markedly to less than half that of the non-illuminated plots. We identified three positive effects of violet light including an &ldquo;immediate-effect&rdquo; on predator attraction, a &ldquo;persistent-effect&rdquo; on predator reproduction, and a &ldquo;secondary-effect&rdquo; on the food web structure. Our results showed that illumination with violet light provides a powerful tool for integrated pest management. This is the first report on the use of illumination to manipulate the behavior of natural enemies.

No MeSH data available.