Push-Pull Method of Controlling Insects – Research

Note: It has been known for a long time that some plants attract some insects while others do not. An integrated approach to control insect pests has used “trap crops” as either early indicators that problems might occur or lure them away from more important crops. It is also well known that some crops repel insects while others do not. There is alot of information being circulated on the net. Some of it is true and others of it are not. Research can be used to confirm or deny it happens and identify what chemicals are responsible for this very important concept.

Ambrosia beetle is more a problem in the tropics than in the temperate climates like the US and in particular the Mojave Desert but the push-pull concept is still interesting.

 Comparison of different methods to assess the seasonal and diurnal activity of ambrosia beetles (Coleoptera: Scolytinae)

Jason B Oliver, Christopher Ranger, Michael E Reding, Samuel Ochieng

Journal of Applied Entomology
November 2018

ABSTRACT
Non‐native ambrosia beetles (Coleoptera: Curculionidae), especially
Xylosandrus compactus (Eichhoff), Xylosandrus crassiusculus
(Motschulsky) and Xylosandrus germanus (Blandford), are destructive
wood‐boring pests of trees in ornamental nurseries and tree fruit
orchards. Previous studies have demonstrated the adults are repelled by
verbenone and strongly attracted to ethanol. We tested a “push–pull”
semiochemical strategy in Ohio, Virginia and Mississippi using verbenone
emitters to “push” beetles away from vulnerable trees and ethanol lures
to “pull” them into annihilative traps. Container‐grown trees were
flood‐stressed to induce ambrosia beetle attacks and then deployed in
the presence or absence of verbenone emitters and a perimeter of
ethanol‐baited interception traps to achieve the following treatment
combinations: (a) untreated control, (b) verbenone only, (c) ethanol
only, and (d) verbenone plus ethanol. Verbenone and ethanol did not
interact to reduce attacks on the flooded trees, nor did verbenone alone
reduce attacks. The ethanol‐baited traps intercepted enough beetles to
reduce attacks on trees deployed in Virginia and Mississippi in 2016,
but not in 2017, or in Ohio in 2016. Xylosandrus germanus, X.
crassiusculus and both Hypothenemus dissimilis Zimmermann and X.
crassiusculus were among the predominant species collected in
ethanol‐baited traps deployed in Ohio, Virginia and Mississippi,
respectively. Xylosandrus germanus and X. crassiusculus were also the
predominant species dissected from trees deployed in Ohio and Virginia,
respectively. While the ethanol‐baited traps showed promise for helping
to protect trees by intercepting ambrosia beetles, the repellent “push”
component (i.e., verbenone) and attractant “pull” component (i.e.,
ethanol) will need to be further optimized in order to implement a
“push–pull” semiochemical strategy.

Take home lesson:  The push pull method of controlling damage from insects is an important concept in natural pest control but it has a ways to go before it can be easily implemented in integrated pest control.