Transcript Vole Management in Citrus

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