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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.


Photographs of experimental plots.(A) Daytime view of eggplant field; (B) Nighttime view of eggplant field with LED illumination.
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f8: Photographs of experimental plots.(A) Daytime view of eggplant field; (B) Nighttime view of eggplant field with LED illumination.

Mentions: A custom-ordered rope light source (3 m long, SHIGRAY Inc., Tokyo, Japan), equipped with LED lights with a peak at 405 nm, was used to illuminate eggplants. The LED rope was mounted on supporting poles above the eggplants (1.4 m from the ground) to illuminate the entire plants. The photon flux density was 0.821 μmol m−2 s−1 at 30 cm from the light source. Lighting time was from 17:00 to 20:00, when O. sauteri activity was high (Fig. 8).


Violet LED light enhances the recruitment of a thrip predator in open fields
Photographs of experimental plots.(A) Daytime view of eggplant field; (B) Nighttime view of eggplant field with LED illumination.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f8: Photographs of experimental plots.(A) Daytime view of eggplant field; (B) Nighttime view of eggplant field with LED illumination.
Mentions: A custom-ordered rope light source (3 m long, SHIGRAY Inc., Tokyo, Japan), equipped with LED lights with a peak at 405 nm, was used to illuminate eggplants. The LED rope was mounted on supporting poles above the eggplants (1.4 m from the ground) to illuminate the entire plants. The photon flux density was 0.821 μmol m−2 s−1 at 30 cm from the light source. Lighting time was from 17:00 to 20:00, when O. sauteri activity was high (Fig. 8).

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.