How to Manage Pests
UC Pest Management Guidelines
A jackrabbit is a hare about the size of a large house cat. It has very long ears, short front legs, and long hind legs. Jackrabbits live in open areas of the Central Valley, coastal valleys, and foothills. They make a depression underneath bushes or other vegetation where they remain secluded during the day. Jackrabbit young are born fully haired, with open eyes, and become active within a few hours.
Cottontail and brush rabbits are smaller than jackrabbits and have shorter ears. They nest where thick shrubs, woods, or rocks and debris provide dense cover. Their young are born naked and blind and stay in the nest for several weeks.
Rabbits are active all year. Jackrabbits prefer trees bordering open areas, such as grassy fields and rangeland. Cottontail and brush rabbits prefer orchards near brushy habitats, ravines, riparian areas, and woodlands favored by these species.
Rabbits and hares can severely damage young trees by chewing bark off the trunk and clipping off low branches to eat buds and young foliage. Rabbits may also gnaw drip irrigation lines. They often live outside of orchards, moving in to feed from early evening to early morning. They damage trees primarily in winter and early spring, when other sources of food are limited.
Prevent damage in a citrus orchard with proper fencing or tree guards. Baiting, shooting, or trapping (depending on the species and the size of the population) are also control options.
Periodically examine young trees for rabbit damage. If you find damage, look for droppings and tracks that indicate rabbits as the cause. Voles also chew the bark from the trunk, but the bark damage caused by rabbits extends higher on the tree and the tooth marks are distinctly larger.
If you find damage, monitor the orchard perimeters in early morning or late evening to see where the rabbits are entering and to get an idea of how many rabbits are involved. You can also estimate the number of rabbits at night by using a spotlight, which produces readily observed "eye shine." Once the trees are 4 or 5 years old, rabbits usually do not present a serious problem.
Rabbit-proof fencing prevents damage to young orchards. Make the fence at least 3 feet tall using woven wire or poultry netting with a mesh diameter of 1 inch or less. Bend the bottom 6 inches of mesh at a 90-degree angle and bury it 6 inches deep, facing away from the orchard, to keep rabbits from digging under the fence. If you are building a fence to exclude deer, and rabbits are a potential problem, it is a good idea to add rabbit-proof fencing along the bottom. Unless you are already building a deer fence, the cost of a rabbit fence may be prohibitive for a large orchard when you are only going to need it for a few years. Individual tree guards are a good alternative.
Tree guards are useful when planting new orchards or replanting trees in established orchards. Cylinders made from wire mesh or some hard plastics provide the best protection against rabbits. Cardboard or heavy paper can also be used, but rabbits may chew through these. Make the cylinders at least 2.5 feet tall to keep jackrabbits from reaching foliage and limbs by standing on their hind legs. Secure the tree guards with stakes or wooden spreaders. Use smaller-mesh wire and bury the bottom few inches of the cylinder if you also need protection against voles.
Poison baits may be practical for controlling large numbers of jackrabbits or for jackrabbits that are damaging trees over a large area. Baits are not registered for use on cottontail or brush rabbits. Before baiting, consult the county agricultural commissioner for restrictions related to endangered species. Follow label directions carefully.
Multiple-dose baits for jackrabbit control must be placed in bait stations specifically designed for rabbits. Place bait stations containing bait near trails and secure them so they cannot easily be tipped over. Use as many stations as necessary to ensure that all jackrabbits have easy access to bait, spacing them 50 to 200 feet apart along the perimeter where jackrabbits are entering the orchard. Inspect the bait stations every morning for the first several days to keep bait supplies replenished; it may take this long before the jackrabbits become accustomed to feeding at the stations. Increase either the amount of bait in the stations or the number of stations if all the bait is consumed in a single night. Replace any bait that becomes wet or moldy. It usually takes 2 to 4 weeks or more before results are seen with multiple-dose baits.
Continue baiting until feeding ceases and you no longer observe any jackrabbits. Make sure to take precautions to prevent domestic animals and wildlife from having access to the bait. Dispose of unused bait properly at the end of the baiting program. Bury the rabbit carcasses on a regular basis.
Shooting, applying repellents, and trapping may provide effective control for small populations of rabbits, or may be used to temporarily reduce damage until other measures such as fences or tree guards are installed.
You can shoot all types of rabbits if they are causing damage to your orchard and if shooting is allowed in your area. If only a small number of rabbits are involved, shooting may be all that is necessary to prevent significant damage while the trees are young. For best results, patrol the orchards at dusk and early in the morning.
Repellents sprayed on foliage or painted on trunks may temporarily prevent rabbit damage. Labels specify the proper application timing. Repeat applications as needed to protect new growth and to replenish any repellent that is washed off by rain or sprinkler irrigation.
Suitable live-catch or kill traps can provide effective control for small populations of cottontail or brush rabbits. Trapping generally is ineffective against jackrabbits because they do not readily enter traps.
UC IPM Pest Management Guidelines:
UC ANR Publication 3441