MD = Mating Disruption
PTB = Peach Tree Borer, found at the trunk-soil interface (most common)
LPTB = Lesser Peach Tree Borer (found on the scaffold limbs, including peaches and cherries)
Talking points from a recent Scaffolds Newsletter (http://www.nysaes.cornell.edu/ent/scaffolds/):
- In NY, there are two species of sesiid (clearwing) moths that attack peaches — the peachtree borer (PTB), Synanthedon exitiosa, and the lesser peachtree borer (LPTB), S. pictipes. The adult borers are striking clear-winged moths with yellow and steel-blue body markings.
- The PTB enters the tree near soil level and does not require the presence of wounds or breaks in the bark for entry, but the LPTB nearly always enters the tree at a pruning scar, canker, mechanical injury, or winter-injured area. The LPTB additionally attacks cherries, causing the same type of injury in the upper trunk and scaffold branches of these trees.
- Injury is caused by larval feeding on the cambium and inner bark of the trunk close to the soil level (PTB) or on the upper trunk and lower scaffold branches (LPTB).
- Control is difficult, owing to the concealed habit of the larvae, growers have traditionally relied on one or more coarse insecticide sprays (e.g., Asana, Lorsban, Proaxis, Thionex, Warrior) of the trunks and lower scaffold branches to deter egg laying and kill newly established larvae. Because this is a labor-intensive measure that often fails to completely control these pests, many growers choose not to elect treatment, or else do an incomplete job, with the intention of getting what they can out of a planting until infestations combine with other peach production factors to warrant tree removal. However, there is a good alternative in the form of pheromone mating disruption (MD) tools for the control of these perennial pests.
- At the end of May each year, Isomate-LPTB ties (CBC) were placed in the test blocks at a rate of approximately 200/acre (1/tree). It should be noted that this blend is formulated to be appropriate at this rate for disruption of both borers in situations where PTB is the predominant species or at least comparable in occurrence to LPTB. Although we assumed that LPTB was the main species at these sites, we chose to be conservative and not use the lower (100 ties/acre) rate recommended for such situations.
- The pheromone dispensers completely suppressed trap catches of both PTB and LPTB at both sites for both seasons, compared with relatively heavy flights noted in the non-disrupted comparison blocks, showing that this pheromone treatment was highly successful in disrupting the chemical communication of males and females of these two species.
- We concluded that these trials provided sufficient evidence that mating disruption alone is able to provide adequate protection from borer infestations in commercial orchards, giving growers an effective non-chemical alternative to trunk sprays for managing this pest complex in their stone fruit plantings.
For the complete article see: http://www.nysaes.cornell.edu/ent/scaffolds/2008/080602.html
Don't underestimate the importance of these pests!