Almonds are not only delicious but nutritious, so many folks are trying their hand at growing their own nuts. Unfortunately, humans aren’t the only ones that enjoy almonds; there are lots of bugs that eat almonds or the tree’s foliage. When treating pests on almond trees, it’s important to recognize almond tree pest symptoms. The following article contains information on almond tree insects and almond pest treatments.
There are quite a few bugs that eat almonds, or rather more commonly the tree’s foliage. Ants, specifically southern fire ants and pavement ants, love almonds as much as you do. Large colonies of these can decimate a nut harvest but are not usually a huge problem.
Aphids and scales, tiny sap sucking vampires, feed in colonies and cause yellow leaf spots, deformity in leaves and flowers. The presence of either of these insects leads to a higher incidence of ants. Why? These insects exude honeydew upon which sooty mold grows, but it also attracts ants. The ants, in return for the honeydew, act as protectors from predatory insects to the scales and aphids.
To rid the tree of scales and aphids, try a hard spray from the garden hose to dislodge them. Prune out and destroy areas of heavy infestation and spray the tree with an insecticidal soap or horticultural oil.
Tent caterpillars feed from April to June, skeletonizing foliage. When there are only a few of these on the tree, treating these pests on almond trees simply requires handpicking and disposing of them. For larger infestations, prune out heavily infested twigs and branches and destroy them. An insecticide might be necessary in the case of large numbers of tent caterpillars.
Leafroller larvae have green bodies with black heads. They feed on almond tree buds just as they are opening. Usually, the population of leafrollers is small and can be left alone, but if there is a large population, Bacillus thuringiensis is often helpful.
Several types of borers may afflict an almond tree. All of them tunnel through the outer layer of bark and into the cambia, or inner wood. Borers are difficult to treat since they are beneath a layer of bark. If the tree is healthy, it will likely not incur any lasting damage from the borers. Heavy infestations may need to be controlled with pesticides. This depends on the type of borer your tree has, so check with your local extension office for information on identifying the borers and insecticide referrals.
Pacific, two-spotted or strawberry spider mites are very tiny insects that spin minute webs. They also suck on the leaves of the tree, resulting in yellowing and premature leaf drop. Spider mites thrive in dry, dusty conditions. To thwart spider mites, keep the tree consistently watered and the surrounding area damp. Also, wash the spider mites off the foliage. For heavy infestations, use an insecticidal soap of horticultural oil during the dormant season.
Leaf footed bugs wear camouflage, leaf-like spurs on their hind legs to protect from predators. Like the almond loving ants, leaf footed bugs also feed on the nuts of the tree as they develop. This can kill the developing seed. They also lay their eggs inside the nut hull which in turn develop abnormally. Leaf footed bugs are most active in early spring but don’t usually infiltrate almond trees. If they do, an application of insecticide might be in order. Even so, this may not kill the eggs residing inside the nut and they may continue to drop from the tree for up to a week post application.
For the most part, almonds are resilient and partially pest resistant. Even the insects listed above have fairly minor almond tree pest symptoms and almond pest treatments are usually of the more benign variety, such as a steady stream of water or the application of horticultural oil or insecticidal soap.
Almond trees (Prunus dulcis) not only provide landscapes with shade, color, fragrance and ornamental beauty, they also produce fresh nuts each year. Almonds originate from Southwestern Asia and the Middle East. Healthy growth of these trees is a direct result of proper growing sites, suitable climates, continued care and insect and disease control.
Every tree has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your tree encounters. If available, disease-resistant trees are the best option for easy care and for all trees, proper maintenance (such as watering, fertilizing, pruning, spraying, weeding, and fall cleanup) can help keep most insects and diseases at bay.
NOTE: This is part 6 in a series of 10 articles. For a complete background on how to grow almond trees , we recommend starting from the beginning.
Trees appear stunted and slow growing leaves may be reduced in size, little or no fruit. If tree is dead, inspect roots for hard, woody ‘tumors’. Note: many things can cause stunted trees.
On 1-year-old shoots, reddish spots develop into sunken cankers. Spots on leaves, center often drops out, leaving small holes. Fruit skins usually are spotted damage to nutmeat unknown. If NOT controlled, production will be reduced.
Usually on bark of young twigs and branches, encrusted with small (1/16”) hard, circular, scaly raised bumps with yellow centers, may also be on fruit. Sap feeding weakens the tree.
Whitish-gray powdery mold or felt-like patches on buds, young leaves and green twigs. Leaves may crinkle and curl upward. New shoots are stunted. Over winters in fallen leaves.
Pale yellow or ‘dirty’ green worms. Leaves are rolled and webbed together where insects feed. Eventually becomes ‘skeletonized’.
Flowers turn brown prematurely. Nuts rot similar to brown rot in peaches. Start as small brown spots, which rapidly enlarge. Fall clean up is important.
Appears as black or brown spots on underside of leaves. Center often falls out leaving a ‘shot hole’ appearance. Leaves may yellow and fall. Fruit will also get spots, sunken areas and cracks.
Young shoots have water-soaked spots which turn brown. Leaves turn black and drop early. Olive colored circular spots on fruit.
Adults of this insect are clearwing moths, metallic blue to black in color with bright bands of orange or yellow. They are about 13 mm long with wings folded and their forewings have a black apical band. Larvae are about 18 mm long, white with brown heads.
Caterpillar is ¾ inch long, reddish orange to yellow. Adult moths have irregular, silver gray and black forewings and legs, snout like at front of the head. Eggs are white at first and later orange before hatching. Larvae are reddish orange then vary from milky white to pink. Pupae are light to dark brown. Larvae bore into nutmeat and later consume most of the nut. Producing large amounts of webbing and a fine powdery residue. Over winter in mummy nuts in tree or on the ground.
Pinpoint size, many different colors. Found on undersides of leaves. Sap feeding causes bronzing of leaves. Severe infestations have some silken webbing.
Insects are ¾ to 1" in length, usually brown in color, have long legs, wings and antennas. They feed on plant tissues that results in tan or bleached spots and distortion. Females lay eggs on the leaves or stems. Can cause nuts to fall early and/or be poorly developed.
Hairy caterpillars that enclose large areas in webbing and feed on enclosed leaves. Remove web with rake and burn. Caterpillare are pulled out with webs.
Adult moths are gray in color and about 1/4 to 1/2 inch in length. Larvae are small brown caterpillars that tunnel into young shoots, killing terminal growth and nuts as they ripen.
Small reddish-purple spots appear on young leaves then enlarge and eventually dropping out of the leaf blade leaving a “shot hole.” It appears on fruit, usually in clustered as light brown spots or lesions with dark purple margins.
Almond trees are hardy in USDA zones 7 through 9 and grow best in locations within these zones experiencing a long growing season. Areas where frosts in early autumn and late springtime are common are not suitable as the tree will not produce a crop of almonds due to the cold weather.
Consider the almond's mature size and width when selecting its permanent location in the landscape. Allow enough space around the tree for proper air circulation because this can help avoid problems with diseases and pests. Do not plant the tree where it will interfere with utility lines or structures. Though classified as small to medium-sized trees, you want to plant the almond in a location where it has enough room to develop its mature shape and size without interference.
Plant the tree in a location receiving full sun throughout the vast majority of the day. Almonds won't grow or bloom well in locations situated in shade. Generally, six to eight hours of sun each day is sufficient for proper growth and production of fruits.
These trees grow well in soils that have some fertility and drain well. The tree will not grow well in soils that retain too much water, or are constantly waterlogged. It will develop rot and eventually die.
For the best growth, almond trees require regular applications of water throughout the growing season. Water the freshly planted tree one or two times a week until the root system establishes itself in approximately two to three months. Thereafter, water the tree weekly.