Location: Fruit and Tree Nut ResearchTitle: Use of entomopathogenic nematodes as a management tactic for weevil pests in pecan
|Shapiro Ilan, David|
Submitted to: Pecan South
Publication Type: Trade Journal
Publication Acceptance Date: 4/10/2023
Publication Date: 5/1/2023
Citation: Slusher, E.K., Shapiro Ilan, D.I. 2023. Use of entomopathogenic nematodes as a management tactic for weevil pests in pecan. Pecan South. Vol 56: 30-37.
Technical Abstract: Several species of weevil feed on pecans with some that are known as major pests (pecan weevil, ambrosia beetle) and some that feed on pecan but their pest status is currently unknown (Fuller rose weevil, two-banded Japanese weevil). While several management tactics are available for controlling these insects, there is always a need to add new tools to growers pest management tool-belts.Entomopathogenic nematodes (EPNs) are a potential option for management of weevils in pecan orchards. Previous research on EPNs has found that they can be very effective tools for pest suppression including for pecan weevil. However, there is always a need to further develop EPN strains to make them cheaper for application and more environmental tolerant. In addition, there is also a need to assess EPN virulence on understudied species such as ambrosia beetle. We conducted two studies that looked to answer both of these issues. For issue one, we tested the effectiveness of two novel persistent strains, NY01 and NY04, against their commercial counterparts, ScAll and SfSN, on pecan weevil, Fuller rose weevil, and two-banded Japanese weevil in pecan orchards in both Oklahoma and Georgia. We found that commercial nematodes were effective at suppressing all three weevil species while the persistent strain was only effective against Fuller rose weevil. Given that the persistent strains often take till the second year to be effective in the field, we will have to wait until this field season to verify their effectiveness. For our second issue, we assessed commercial EPN strains on two species of ambrosia beetle: granulate ambrosia beetle and black stem borer. We found that while most of the commercial strains were effective in uppressing both ambrosia beetle species, there were differences in strain effectiveness against the two ambrosia beetle species. Further research will be needed to see what caused these differences. Overall, we found some evidence for virulence of EPNs against ambrosia beetle in pecan. However, given this was our first year of data, we will have to wait and see how things shape out in our second year before we can draw any strong conclusions. Our research will help to enhance the ability of pecan growers to control weevil pests in an environmentally friendly fashion.