Ground squirrels are serious agricultural pests causing damage from $30 to $50 million annually in California alone (Marsh, 1994). They do much immediate damage, and also create problems that may surface later on. Damage ranges from chewing on trees and irrigation lines, eating crops, destruction from burrowing, and disease such as plague.
Early recognition of potential and actual damage, and early control are stressed, as ground squirrels readily adapt to new environments and may establish large populations in a short period of time. If you notice ground squirrels on your property, begin monitoring them immediately.
Crops – Even if California ground squirrels do not often live in crops because they are too wet, they can still be a serious threat when they live on the perimeter and feed inward on the fields.
Trees and Vines – Squirrels cause damage to fruit and nuts, chew at the bark, and burrow under the trees.
Rangeland and Irrigated Pastures – Ground squirrels compete with grazing animals for forage. They also reduce the potential because they eat the tender young sprouts of annuals, which may retard or stop growth. Additionally, their burrow creates large holes that may be a danger to animals such as horses and cattle.
Disease – California ground squirrels are known to be carriers of bubonic plague.
Irrigation – Squirrels will chew on irrigation lines.
Erosion – Burrowing by ground squirrels can be very destructive. It is a problem in levees, on roads, and in pastures where burrows lead to severe erosion, tripping injuries, and damaged equipment.
Other --Since ground squirrels are so adaptable to the environment they are in, they have been found causing problems in many other areas.