This amount should be placed six inches to three feet out from trunk and watered in immediately and thoroughly.
Insect Control
Do not spray young trees for pests that attack the crop until after they start bearing fruit.
See this link for pest management:
http://www.ipm.ucdavis.edu/PMG/selectnewpest.citrus.html
Vertebrate Pests
Young fruit trees are especially liable to severe damage from gophers, rabbits, voles (mice) and deer.
Rodents Pocket gophers eat roots, bulbs and entire young plants. Eradication by trapping is the most efficient method. Two types of traps are commonly used: box traps and Macabee traps. Poison baits are effective, but can cause harm to dogs and cats if eaten.
Moles are only present in good soils as they are primarily insect eaters (especially earthworms and larvae). A spear or harpoon trap is usually used for control.
Ground Squirrels (Gray Diggers) gnaw roots and bark and will climb trees for fruits and nuts. Controls are baited box-type traps placed near burrows, anticoagulant poison-bait placed inside burrows, and gas bombs placed in the burrow. Metal guards around tree trunks will prevent them from climbing up into trees.
Birds The only sure solution to bird depredation is to use screening or netting material. This must be tied about the tree trunk to be effective in keeping the birds out. The use of owl statues, flexible snakes and cat statues will only be effective in gardens if they are repositioned every few days.
Deer They will spend more time looking for food in gardens as wild plants dry out, and will eat foliage and fruit of nearly anything that grows. The only fool-proof protection against their depredation is fencing. On level ground a seven foot woven-wire fence will usually suffice. An "outrigger" extension on top makes it harder to jump. Individual wire cages around plants and cylinders of wire around trees may be effective also. Repellents can work if renewed frequently, especially after each rain, watering or several days of exposure.
Weeds
If you want good growth, it is imperative that weeds are not allowed to develop near your trees. Keep the space clean for a full six feet from the base of your tree. Allow no weeds or grass to grow in this area and apply no systemic weed killers that may be absorbed by the tree roots. Mulching (keeping it away from the trunk) can be very effective at controlling weeds.
If you would like more information: Master Gardener Helpline,email at mgventura@ucdavis,edu or call us (805) 645-1455.