By the Chemtura AgroSolutions team of experts
The variegated leafhopper can be a major nemesis of vineyards — or simply a nuisance. Therefore, management may be a little tricky because vines can tolerate fairly high populations without harm, and predators and parasites may be able to maintain leafhopper populations below tolerance levels.
As with most pests, scouting and monitoring leafhopper populations is the key to making informed treatment decisions and preventing leafhoppers from reaching damaging levels.
According to Integrated Pest Management experts with the University of California, whenever nymphs first appear, begin sampling for leafhoppers. Randomly select 20 vines in each block of the vineyard, each at least a few vines in from the end of the row. Look for:
1. First generation nymphs — On each vine, choose one leaf at the 3rd or 4th node up from the basal node.
2. Second and third generation nymphs — Choose young but fully expanded leaves in the middle of the canes.
- Count nymphs on underside of each leaf. Note whether they are grape leafhopper nymphs, variegated leafhopper nymphs, or both.
- Check the leaves for red, parasitized eggs or eggs with emergence holes.
3. Use this monitoring form to help keep track of leafhopper populations.
4. Continue monitoring weekly until harvest.
Meanwhile, continue monitoring for spider mites as well, since populations of this season-long pest can quickly explode when conditions are right. Make sure Acramite® 50WS, which delivers good knockdown mite control without affecting beneficials, is part of your arsenal. Acramite eliminates the majority of undesirable mites, giving beneficial insects a head start in keeping mite populations in check. Plus, its unique carbazate chemistry also makes Acramite an excellent rotational miticide for resistance management.
Always read and follow label directions.
Also visit with your PCA or Chemtura AgroSolutions™ representative for additional ways to enhance your control program and ensure a successful season:
• Mike Ansolabehere, Southern San Joaquin Valley: (661) 304-3023; email Mike.Ansolabehere@Chemtura.com
• Matt Loftus, Central San Joaquin Valley: (559) 960-1112; email Matthew.Loftus@Chemtura.com
• Eric Leer, North Central California: (209) 531-6478; email