By John Wood, Certis USA Regional Manager
Spring is in full swing and so are the pests that come with it. Peach twig borer, (PTB), nematodes and insect pests are hard at work to destroy your trees. Fortunately, there are effective methods to manage them.
The first insect management tool I want to mention is new BoteGHA® ES Mycoinsecticide, which contains spores of the entomopathogenic (insect-killing) fungus Beauveria bassiana. BoteGHA® controls aphids, leafhoppers, planthoppers, mealybugs, psyllids, thrips and whiteflies.
BoteGHA® ES is an emulsifiable suspension (ES) that does not require refrigeration. It is tank mix compatible with many insecticides. Before mixing, confirm compatibility by using the online guide at certisusa.com/pdf-technical/BoteGHA_ES_compatibility.pdf or by contacting your local Certis representative. When an insect comes in contact with BoteGHA®, the fungal spores adhere to its body and germinate. The fungus emerging from the spore produces enzymes that allow it to penetrate the insect cuticle and grow within the insect’s body, killing it.
BoteGHA® has a 4-hour REI and its nontoxic mode of action presents low risk to applicators and handlers. It also presents low risk to beneficial species and the environment compared to some other insecticides. It is OMRI-listed and NOP-approved, is residue-exempt and fits well as part of a resistance management plan.
PTB overwinters as 1st or 2nd instar larvae in the limb crotches of young branches. As weather warms, the larvae begin feeding in the hibernacula and create chimneys of frass. Following this growth stage, the larvae emerge and begin feeding on flower buds and new foliage. They then mine into tips of new shoots and create the dead shoot tips, or flagging, that is commonly observed in infested orchards.
In April and May, the moths that develop from this overwintering generation emerge, followed by three successive generations to make four generations in a normal year. Larvae feed and develop on nuts or in shoots and the final generation develops the overwintering hibernacula after emerging from their eggs.
Deliver® Bt Biological Insecticide is a highly effective tool to help manage PTB. It contains a higher concentration of the insecticidal Cry1Ac delta-endotoxin than any other Bt product, which gives it higher potency pound-for-pound against these pests. Deliver® is OMRI-listed and NOP-approved and is residue-exempt, an important consideration for exporters. It is compatible with our new BoteGHA® ES Mycoinsecticide and also approved for conventional orchards.
Remember, Deliver® and other Bt products are only effective against the larval stages of PTB. The larvae must ingest the Bt for it to be effective. This means Bt spray deposits must be present on plant surfaces when the larvae are actively feeding.
Deliver® is also effective in soft control programs for PTB. Typically, dormant sprays may kill beneficial predators of PTB in orchards, but Bts aren’t harmful to bees and other beneficials.
You’ll know whether beneficials are parasitizing PTB when you scout the hibernacula. Empty hibernacula (with no frass to indicate recent PTB feeding), or hibernacula containing only head capsules or other remains of dead larvae are all positive signs that natural control agents are at work.
Control nematodes now
I recommended using MeloCon® WG Biological Nematicide to help control nematodes in the last issue. It bears repeating. Some tree roots are still flushing and that active rhizosphere at the tips has plenty of exudates that nematodes like. There is still time to apply MeloCon® to the soil and protect roots. It has a 4-hour REI and is also residue-exempt.
This spring is like any other. We have to stay on our toes to keep pest pressures as low as possible. Let me know how any of us on the Certis team can help. Thank you for your ongoing input. Until next time, when we will discuss Seduce™ Insect Bait use and its efficacy in a wide variety of crops.