ARS | Publication request: Barriers in a tropical orchard landscape: how the presence or absence of hedges influences insect dispersal in mixed orchards of Carica papaya and Manilkara zapota.

Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 30, 2009
Publication Date: N/A

Interpretive Summary: The Puerto Rican May beetle can be very devastating to fruit crops, particularly seedlings. In orchards where this beetle exists in high densities, it is very difficult to control these beetles and reduce the damage they cause. There is evidence that this beetle can be influenced by physical barriers such as hedges around the orchard. In our experiment we compared the incidence of this beetle in orchards or papaya and sapodilla with and without barrier hedges. In addition, we looked at the impact these barriers had on other insect pests of these fruit trees. The only insect affected by the hedges was the Puerto Rican May beetle, which was less numerous in orchards that had a barrier of tall grass around the orchard than in orchards that had no grass hedges. This information could be useful in developing management strategies against this pest.

Technical Abstract: The presence of plants in the form of a hedge may hinder or alter movement of certain insects into and within an orchard. We investigated the impact that the presence of a hedge of tall grass had on infestation by various pests into mixed orchards of papaya and sapodilla. For most insects there was no discernible effect: these insects were equally liable to be found in orchards with a hedge or in orchards without a hedge. However, one insect showed a dramatic response to the presence of hedges. Phyllophaga vandinei (Coleoptera: Scarabaeidae) was much more prevalent in orchards without a hedge than in orchards with a hedge. The distribution of P. vandinei within other orchards indicate strong edge effects (more beetles on the edge of an orchard) as well as a tendency to congregate on the southeast corner of orchards. This information can be used to implement management strategies against this pest.