Insecticide For Peach Trees

Peach trees require specific care to produce a good harvest of fruit. Peach trees are subject to certain pest and diseases, so there are pesticides that should be applied at the right time of year. Peach tree problems can often be prevented by a regular spraying programme.

Insecticide For Peach Trees

Insect Pests of Peaches and Plums

Plum Curculio

The plum curculio, Conotrachelus nenuphar, is one of the most damaging insect pests of homegrown peaches and plums. The white, legless grubs are the “worms” so often encountered in fruit that has not been adequately protected. Adults are small weevils that overwinter in leaf litter and ground trash in or near the orchard. The adults become active about the time peaches begin to bloom. They fly to trees to feed on buds and newly set fruit; females chew crescent-shaped punctures through the skin of developing fruit to insert their eggs. Grubs hatch and feed inside the fruit until mature. Fruit that are attacked when small usually abort, but larger fruit remain on the tree with developing larvae inside. Picking up and destroying fallen fruit can help reduce future infestations. Mature larvae drop to the ground when they are ready to pupate. There are two to three generations per year.

Successful control of plum curculios depends on killing the adults before they are able to lay their eggs in the fruit. Begin including malathion in cover sprays as soon as petals fall and apply on a 10- to 14-day schedule (tighten the spray schedule during rainy periods). Extending the spray intervals will result in reduced control. Tightening spray intervals to 7–10 days, especially for the first few cover sprays, will improve control. The first few sprays after petal drop are the most important because they target the overwintered adults that will lay the eggs for the first generation.

Stink Bugs and Plant Bugs

Several species of stink bugs, as well as tarnished plant bugs, will feed on developing peaches and plums, causing catfacing injury. It is usually adult insects that cause this damage. Their feeding kills developing cells at the feeding site and causes the fruit to be distorted as it grows. Cover sprays containing malathion will usually control catfacing insects. Permethrin is also effective against stink bugs and will control plant bugs in non-Delta areas of the state.

Oriental Fruit Moth

The caterpillar stage of the oriental fruit moth, Grapholita molesta, bores into the terminals, or tips, of peach tree branches, causing them to die back 4–6 inches. This damage is not serious unless populations are high, but once the terminals harden and become unattractive, the caterpillars begin boring into fruit.

The oriental fruit moth is relatively uncommon but can cause significant fruit damage. Watch for early signs of dying terminals and tighten the cover spray interval if necessary to protect fruit. Infested fruit may have masses of gummy sap containing frass at the point of entry. Permethrin can be substituted for malathion if necessary to control heavy infestations.

Peachtree Borers

Two species of peachtree borers attack peaches and plums: peachtree borer (PTB), Synanthedon exitiosa, and lesser peachtree borer, Synanthedon pictipes. Both are wasp-like, day-flying moths whose larvae bore under the bark and tunnel in the cambium. Peach tree borers usually focus their attack on the lower 10–12 inches of the trunk down to the root flare and extending a few inches belowground. Lesser peach tree borers attack higher on the trunk and on lower scaffold limbs. Peach tree borers are the more damaging of these two species.

Moths are especially attracted to trees that have injured areas on the trunk or have previous bore infestations. Keeping trees healthy and protecting trunks and root flares from mechanical injury helps reduce attacks. The eggs are deposited on the surface of the bark, and newly hatched larvae promptly bore into the tree. If PTB are not controlled, trees may die as the result of the cumulative damage caused by larvae tunneling through the cambium. Young, small-diameter trees are especially vulnerable. Balls of gummy sap that contain frass and sawdust indicate bore infestation. Note that some disease infections also cause peach and plum trees to exude gummy balls of sap through the bark. Sap balls that contain frass and/or sawdust indicate a bore problem; sap balls that are clear/free of frass and sawdust indicate disease problems.

The key to controlling peach tree borers is to kill the newly hatched larvae before they bore through the bark. This means applying a trunk spray at the proper time of year so the newly hatched larvae have to crawl through the insecticide residue as they bore into the bark. Low numbers of moths may be active in June and July, but cover sprays for other insect pests usually control these. Heavy PTB moth flight does not occur until August and September, usually peaking around early September, and this is the time to apply trunk sprays for peachtree borer control.

Permethrin is currently the best treatment available for peachtree borers in small home orchards. Mix at the highest rate labeled for trunk sprays, and thoroughly spray the lower scaffold limbs, the trunk, and the root flare. Apply a second spray in 2–3 weeks; a single application of permethrin will not provide adequate residual control. Treatment dates around mid-August and the first week of September are appropriate for most of the state. To protect trees that are heavily infested or especially vulnerable, make three applications at 2-week intervals, beginning in mid-August.

Granulate Ambrosia Beetle

This tiny beetle occasionally attacks and kills peach and plum trees, as well as many other trees in the home landscape. Actually, it is not the beetle that kills the tree, but the disease it carries and inoculates into the tree. Because they are less than one-eighth of an inch long, the beetles themselves are rarely seen. The sign to look for is the compacted columns of sawdust these beetles create as they bore into the tree. Except for the fact that they are often curved, these sawdust columns are similar to toothpicks in size and color. Be aware, however, that this sign is short-lived, as these sawdust columns are easily broken off by wind and rain.

Even a half-dozen attacks is enough to kill a small tree, and there is no effective rescue treatment. This pest has several generations per year, but most fatal attacks to fruit trees occur in early spring, just as trees are leafing out. These beetles attack many species of trees and shrubs, but peaches and plums seem to be favorite targets, possibly because of pruning activities. Newly planted trees, less than 3 or 4 years old, are most susceptible, but older trees are also attacked.

Fortunately, granulate ambrosia beetle attacks are sporadic; they may kill two or three of your seven trees one year and not return for several years. In most situations, there is no practical treatment or response other than to recognize what killed the tree and to cut it down and burn the wood to prevent further spread. To treat preventively, mix permethrin according to label directions for a trunk spray and apply at 2-week intervals, beginning just before buds begin to swell and continuing until just before bloom. Spray to cover the trunk, scaffold limbs, and larger branches. Trees less than 4 years old are most likely to benefit from such treatments. Note that sprays for ambrosia beetles must be applied much higher on the tree than for peachtree borers.

Scale Insects

Heavy infestations of San Jose scale or white peach scale can severely damage peach and plum trees. Scale infestations are difficult to detect because the insects are small and immobile. Watch for irregular, crusty, brown or white patches on limbs and twigs, and then use a hand lens to see individual insects (Figure 3). Scales will also occur on fruit when infestations are heavy. Insecticides used in spring and summer cover sprays help control newly hatched scale crawlers, but dormant horticultural oil sprays are the most effective treatment for scales. Apply a single delayed-dormant treatment in late winter to early spring as a preventive treatment or to control light infestations. Trees that are heavily infested with scales should be treated in late fall, after 95 percent leaf drop and before onset of freezing temperatures, and again in late winter to early spring (delayed-dormant period). Apply spring oil sprays before buds break and new leaf growth is evident. Do not apply oil sprays within 30 days of (before or after) making a spray that contains sulfur.

Mites

Several species of mites attack peaches and plums. Two-spotted spider mites are the most common, but European red mites and silver mites may also occur. Heavy infestations of spider mites can be damaging and difficult to control because there are no effective miticides labeled for home use. Minimize foliar sprays containing pyrethroid insecticides, such as permethrin, and avoid treatments that contain carbaryl (Sevin) because these treatments tend to encourage spider mite outbreaks. Some mites overwinter as eggs on the bark, and these overwintering eggs can be controlled with a delayed/dormant application of horticultural oil. If heavy mite populations occurred in the previous season, make an application of horticultural oil just before bud break to help reduce the potential for further mite outbreaks.

Protect bees and other pollinators. Avoid spraying insecticides while fruit trees are in bloom. There are no major insect pest problems to be concerned about during this period anyway. Begin your insecticide spray program promptly after petal drop to control overwintered curculios and catfacing insects.

Insecticides for Homegrown Peaches and Plums

Horticultural Oils

Horticultural oils are usually applied in winter to early spring, after leaves drop in the fall and before buds break, to control San Jose scale and white peach scale, as well as overwintering mites. Read and follow the label carefully to avoid injuring plants. Avoid applying horticultural oil sprays when temperatures are below freezing or are likely to drop below freezing for the next 2–3 days. Bonide All Seasons Horticultural Spray Oil and Ortho Volck Oil are two examples.

Malathion

Malathion is the most effective treatment available to homeowners for controlling plum curculios and is the key insecticide recommended for early cover sprays (beginning at petal fall). Malathion is also effective against immature scale insects (crawler stage) and catfacing insects (stink bugs and plant bugs) and will help control oriental fruit moths and lesser peach tree borers. Examples of brand name formulations include Bonide Malathion Concentrate and Ortho Malathion Insect Spray. The pre-harvest interval for malathion is 7 days on peaches. Avoid applying malathion during periods of overcast or highly humid weather because the spray will dry slowly and increase the potential for plant injury.

Permethrin

Permethrin is a pyrethroid insecticide that controls a wide range of insects. It is the most effective treatment currently available to homeowners for control of peach tree borers. Because overuse of permethrin can trigger outbreaks of spider mites, scales, and aphids, it is not recommended for early cover sprays. Permethrin is effective against oriental fruit moths and catfacing insects, as well as plum curculios, and can be substituted for malathion in one or two of the summer cover sprays. There are many commercial formulations of permethrin that are not labeled for use on peaches and plums. Check labels carefully before you buy. Hi-Yield Lawn, Garden, Pet, and Livestock Spray (10%) and Bonide Total Pest Control Outdoor Concentrate (13.3%) are examples of two products that are labeled for use on peaches. The pre-harvest interval for permethrin is 7 days on peaches.

Pre-Mixed Fruit Tree Sprays

Several companies sell pre-mixed fruit tree sprays. These usually contain a fungicide and one or more insecticides. Malathion should be one of the insecticides. Bonide Complete Fruit Tree Spray Concentrate and Gordon’s Liquid Fruit Tree Spray are two examples (both contain 11.76% Captan, 6% malathion, and 0.3% carbaryl). Such products can be an effective and convenient way to buy and apply pesticides, but read the label carefully before purchasing to be sure the product contains the active ingredients you need. Some “fruit tree sprays” contain active ingredients that are only marginally effective against important insect and disease pests.

Insecticide For Peach Trees

 

Peach trees are susceptible to a number of insects, including aphids and peach leaf curl. These insects can cause significant damage to your tree if left untreated. In order to prevent damage, it is important to identify the insect and treat it accordingly.

Aphids are small, sap-sucking insects that are often yellow or green in color. They can hide in the crevices of leaves or on the stems of plants and spread disease through their saliva. Aphids tend to congregate around new growth because they feed on young, tender stems and leaves.

If you notice lots of little bugs on your tree or see them crawling around in large groups, it is likely that you have an aphid infestation. If you notice these signs, treat your tree with an insecticide for peaches that contains pyrethrin as its active ingredient. Pyrethrin is toxic to all insects but does not harm humans or animals.

List Of Insecticide For Peach Trees