How to Manage Pests
UC Pest Management Guidelines
Scientific Name: Lepus californicus
(Reviewed 7/13, updated 7/13)
In this Guideline:
DESCRIPTION OF THE PEST
Jackrabbits occasionally damage asparagus. Identifying characteristics:
The desert cottontail (Sylvilagus audubonii) and brush rabbit (S. bachmani) are sometimes confused with jackrabbits. However, these species are substantially smaller, have shorter ears, and are typically found in brushy or wooded areas.
Jackrabbits are usually found in open or semi-open areas of valleys and foothills; they are seldom found in dense brush or woodlands. A good sign that jackrabbits are present is their coarse, circular fecal droppings or pellets found scattered over an area. They also make a depression in the soil, called a form, beneath a bush or other vegetation and use it for hiding and resting during the day.
What jackrabbits eat is variable depending on location and the availability of appropriate plants. They prefer succulent green vegetation; grasses and herbaceous plants typically make up the bulk of their diet. Feeding usually begins during the evening hours and continues throughout the night into the early morning. Jackrabbits do not need to drink water.
If food and other necessary resources are found in one place, jackrabbits will stay in the area. If food and areas for shelter are separated, jackrabbits will move between these areas in the morning and evening. Daily travel of 1 to 2 miles round trip between these areas is not uncommon. These travels are habitually made on the same trails every day, producing noticeable paths through herbaceous vegetation.
Jackrabbits occasionally feed on asparagus spears during the harvest season. Otherwise, jackrabbits cause little direct damage to asparagus.
Jackrabbits can carry tularemia, otherwise known as rabbit fever. This disease is relatively rare in humans but can be contracted by handling an infected rabbit with bare hands or by eating insufficiently cooked rabbit meat. Do not handle rabbits with bare hands.
Manage rabbits through exclusion, baiting, and shooting. Unfortunately, habitat control is not typically effective for jackrabbits given their ability to cover great distances between forage and shelter locations. The choice of control method should depend on the urgency of the problem and the situation.
Monitoring and Treatment Decisions
Be observant for jackrabbits or their signs.
If severe damage is expected, you may wish to consider exclusion methods before serious damage occurs.
Where jackrabbits are a constant and continuing threat to asparagus, fencing the entire field may be the best management approach. To make an effective barrier build a fence no less than 36 inches high, which jackrabbits will normally not jump.
Temporary fences using silt fencing can be used to exclude jackrabbits in fields where a permanent fence is not required; this would provide a less expensive alternative for exclusion. The fence bottom must not have any access points where jackrabbits can crawl under. Pinning with staples (e.g., those used for nursery groundcover fabric) every few inches or burying the bottom in a trench as previously described will exclude rabbits.
Poison baits offer a practical and economical way to control large numbers of jackrabbits in large areas, although results are sometimes erratic. Only multiple-dose anticoagulant baits (e.g., diphacinone) are registered for use against jackrabbits. All field-use anticoagulant baits are now restricted-use materials; you will need to be certified to use these baits for jackrabbit control. They come in grain or pelletized formulations that may be used along field edges, but not within the field itself.
Be careful to place poisoned bait where domestic animals and humans—especially children—cannot pick it up. Be aware of all wildlife in the area, such as doves or pheasants, and take precautions to protect them from poisoning. Protect diurnal seed-eating birds by removing or covering the bait during daylight hours and exposing it only at night.
When jackrabbit populations are small, shooting can be an effective control. Patrol in the early morning and late evening when jackrabbits are more active.
Keep in mind that lead bullets are no longer allowed in California condor ranges. In this area, alternative bullets must be used. They can be more expensive and may not be available depending on the caliber of gun used. Additional information on this lead ban can be found at http://www.dfg.ca.gov/wildlife/hunting/condor/.
Jackrabbits are difficult to capture because they avoid confined spaces. So trapping is rarely an effective approach.
Repellents are occasionally effective at deterring jackrabbit damage to some crops. However, no effective rabbit repellents are available for use in asparagus.
There are number of predators that will feed on jackrabbits including coyotes (Canis latrans), bobcats (Lynx rufus), and raptors. When predator populations are high, they may lower jackrabbit numbers in some areas. However, you should not rely on them to control jackrabbits; predators are rarely able to control jackrabbit numbers at sufficient levels to prevent damage.
UC IPM Pest Management Guidelines: