Neil O’Connell University of California Cooperative Extension Tulare County

Vole Management in Citrus

Vole Management Voles are also known as Meadow Mice Five species in California Two species known to cause damage Microtus californicus, M.montanus

Vole Damage Damage from voles: Permanent pasture,alfalfa hay,various vegetable crops, grains,nursery stock,apple,avocado,citrus,cherry,olives.

Damage from Vole Feeding

Vole Habitat Microtus are often found where there is grass cover Voles establish “runs or trails” in the cover Voles are active all year long

Vole Activity Voles are chiefly nocturnal-active at night; may forage at any time of day or night

Vole Habits Voles are usually found in colonies Vole colonies usually associated with 2 inch wide runways through the grass Signs of vole presence usually marked by small brown fecal pellets and pieces of grass along runways

Vole Runway With Burrow

Vole Colonies Mice may feed beyond runways They feed on roots,seeds,succulent stems, and leaves

Vole Burrow

Vole Burrows Burrows are made up of extensive tunnels,nest chambers and storage chambers. Tunnels are extensive and shallow This may limit the effectiveness of some treatments

Vole Colony With Burrows

Vole Reproduction Female Microtus may produce 5-10 litters per year with an average of 4 young per litter. Breeding coincides with growth of forage Peak populations occur every 3-4 years followed by a rapid decline Declines result from lack of forage, disease, overcrowding,predators Predators include coyotes,owls, snakes

Predator Activity Predators are not able to prevent or control rapid buildup of vole populations

Vole Presence Permanent habitat is along roadsides, ditch banks, or adjacent to cultivated crops Invasion into cultivated crops results when permanent habitat not favorable or population of voles is increasing

Additional Habitat for Voles Plastic ground cover provides cover for voles Feeding damage may go unnoticed

Burrow Under Tarp

Vole Management Meadow mice are classified as non- game mammals by California Fish and Game Department Non- game animals injuring a crop may be taken at any time, by any means by owner or manager

Vole Management Reduce ground cover Use of toxic baits

Vole Management Toxic bait- carrier is often oats or wheat with a toxicant

Toxic Baits Primary toxicants used: zinc phosphide, diphacinone, chlorophacinone Agricultural commissioner’s office(Tulare,Kings,Fresno counties) have baits-check with them if they have a bait for use in citrus for management of voles

Vole Damage-Trunk Girdled

Vole Damage-Roots and Trunk

Watch for Burrows in the Orchard