Effects of Herbivore-Induced Plant Volatiles in Various Maturity Stages of Pepper on the Attractiveness of Orius insidiosus

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Commodities

• Vegetables: peppers

Practices

• Pest Management: biological control

Flower thrips are worldwide pests and pose major threats as the sole vectors of tospoviruses, and affect numerous fruiting vegetable crops grown throughout the Southern region. Growers are faced with increasing challenges as thrips have developed resistance to many classes of insecticides due to a heavy reliance upon scheduled applications. In an effort to develop a sustainable integrated pest management program for pepper plants, studies have focused on exploiting naturally-occurring predators of thrips, such as the minute pirate bug Orius insidiosus.

Host plant responses to herbivory have been shown to aid in the attraction of natural enemies through the release of herbivore-induced plant volatiles. Furthermore, mixtures of multiple herbivore-induced volatiles released by different species of conspecific host plants have been shown, in some experiments, to be more attractive to flower thrips predators than volatiles produced by a single species of host plant. The effects of multiple herbivore-induced plant volatiles produced by similar conspecific host plants at different developmental stages, however, are not yet fully understood.

Determining the differences among multiple herbivore-induced plant volatiles released from pepper plants at varying maturity stages can provide insight into the ability of pepper plants to attract natural predators and, consequently, disperse pests more effectively than pepper plants of the same maturity stage. The understanding of these relationships is vital for promoting of the use of natural enemies as part of an integrated pest management program for vegetables aimed at reducing insecticide use and increasing benefits for growers, as well as the environment and community.

1. Determine the composition of single herbivore-induced plant produced by the different stages of pepper plant (vegetative vs. flowering) under direct herbivore attack.
2. Determine multiple herbivore-induced plant volatiles produced by the different stages of pepper plant (vegetative vs. flowering) while:
a. Under direct herbivore attack
b. Eavesdropping on neighboring infested plants
3. Determine if herbivore-induced plant volatiles released vary when under direct herbivore attack vs. those released in response to eavesdropping.
4. Determine if combinations of those multiple herbivore-induced plant volatiles without visual cues are more attractive to natural predators (O. insidiosus) than the single volatiles produced by the same stages using:
a. Olfactometer Y-tube testing
b. Ethovision video tracking software
5. Determine if combinations of those multiple herbivore-induced plant volatiles with visual cues are more attractive to natural predators (O. insidiosus) than the single volatiles produced by the same stages using field-cage experiments.
6. Determine the use of attractive volatiles for O. insidiosus in field conditions.