What is the best time of year to spray fruit trees? — Tips from Bob Vila

depotphotos.com

Q: The fruits of several fruit trees in my garden are growing poorly and the leaves are looking bad. I probably need to spray the trees, but I don’t know how to go about it. Can you tell me when to spray fruit trees?

A: Fruit tree maintenance is a year-round job and includes pruning, fertilizing, removing diseased fruit, and spraying at different times of the year. Timing is critical for each of these tasks. During active growth, trees absorb and use nutrients from fertilizers.

To know when to spray fruit trees for pests, you must first know what threatens the tree and when the threat is active. An insect egg may lie dormant in the bark of an apple tree all winter, only to hatch and feed on the leaves in the spring. Or a particular fungal spore may infect a peach tree only when the blossoms are open.

Develop a fruit tree spray schedule based on the growth cycle and threat.

Timely tree spray applications for disease and insect control. The timing coincides with the development of plants and fruits, as well as the climate and weather conditions. Watch for specific growth stages with observable characteristics:

  1. Dormancy is before the buds begin to swell in the spring.
  2. Pre-flowering stage includes five distinct growth stages for tree buds before flowers open:
    1. silver buds
    2. green tips
    3. half inch green
    4. tight clusters (of flower buds)
    5. pink flower buds (but not yet open).
  3. To bloom is from when the first flower opens until the last petal falls.
  4. petal fall is the time after flowering, before the first small fruits begin to develop.
  5. Fruit formation is the last stage, which lasts until the harvest.
when to spray fruit trees

depotphotos.com

Avoid spraying fruit trees when flowers are open, as insecticides sprayed at this time kill bees and other pollinators. Read and follow all safety precautions to minimize personal exposure to pesticides. Always follow mixing instructions. Increasing the concentration of a spray does not kill insects faster, may kill more beneficial species, and increases the chance of runoff contaminating local streams and groundwater.

  • dormant spray, or dormant oil, is a horticultural oil that kills overwintering scale insects, mealybugs, mites, aphids, and other pests on bark. The oil has either a mineral base (petroleum) or a vegetable base. One dormant spray application for fruit trees per year, or less, is typical. Plantonix Organic Neem Bliss is an effective and organic spray for fruit trees against overwintering pests.
  • Insecticidal sprays kills insects that feed on foliage, burrow into trunks or spoil developing fruit. Most fruits require multiple applications throughout the growing season for active insects. Avoid spraying insecticides when flowers are present. BioAdvanced Vegetable and Garden Bug Spray protects fruit and lasts longer than some sprays.
  • Fungicide sprays control the spread of fungal diseases. You may need to apply fungicide multiple times throughout the growing season to protect against different diseases. Many of these products can damage or kill pollinators, so avoid spraying fungicide when flowers are open. Grower’s Ally Fungicide Concentrate can protect fruits and vegetables.
  • General purpose aerosols control most insects and diseases affecting fruit trees; it is easier to spray a single product at set intervals throughout the growing season than to schedule a specific fruit spray. However, using only a general purpose fruit tree spray increases unnecessary exposure to pesticides and may not control some insects and diseases. Try Bonide’s Orchard Spray, a concentrate for citrus, nut and fruit trees.
  • Foliar fertilizer sprays micronutrients such as zinc, copper, magnesium, molybdenum, boron and calcium can promote fruit development where these nutrients are lacking or unavailable due to soil alkalinity. These elements mix with water and spray directly onto the leaves, which absorb nutrients and move them to developing fruit. Strictly follow label instructions to avoid damage to trees. Consider Bloom City’s Oganic SuperGreen, which contains helpful magnesium and kelp.
when to spray fruit trees

depotphotos.com

If there has been intense pest activity during the previous growing season, udormant spray for fruit trees in late winter or early spring.

Dormant sprays kill insect pests that overwinter on fruit trees. Unless pest populations are skyrocketing, there is no need to spray dormant oil every year. Every 3 to 5 years is typical.

Finish the dormant spray before the buds begin to swell. Apply dormant spray only when the temperature is above 40 degrees Fahrenheit. Be sure to fully cover all surfaces, paying particular attention to the undersides of the branches and the crotch of the branches.

Apply insecticide sprays as needed at 2-week intervals, from green tip until bloom, and from petal fall until harvest.

It is possible for insects to develop a tolerance to even the best insecticide if it is used repeatedly. The solution is to alternate the application of insecticides with other active ingredients.

If you primarily use a general purpose spray to kill insects and disease, alternate treatments using a specific purpose insecticide to eliminate the risk of pests developing a tolerance to either product chemical. Insecticidal soap such as Natria Insecticidal Soap can be used up to the day of harvest.

when to spray fruit trees

istockphoto.com

Each type of fruit tree has its own ideal fungicide spray schedule depending on the diseases that threaten it.

Targeted, stand-alone fungicide treatments improve fruit quality when applied at the right time. Fruit disease spores infect their hosts when environmental conditions are ideal.

Some fungal spores become active in cool, wet weather in the spring. Other diseases spread in hot, humid summer conditions. It is important to anticipate plant diseases and start treating them just before they arrive.

Fungicide applications are most critical during the green tip through petal fall stages of apple and pear trees. Peach and plum trees require disease control treatments in the spring, summer and fall for best results.

Find the timing of application on the product label to prevent specific diseases or see this extension guide from Purdue University for growth stage and fruit tree spray schedules specific to common fruits.

when to spray fruit trees

depotphotos.com

Use a general purpose sprayer for fruit trees at 1-2 week intervals after key observations of plant development.

Apply spray first at green tip, followed by pre-bloom, full pink, petal fall, first coverage (1 week after petal fall) and second coverage (2 weeks after falling petals).

General purpose fruit tree sprays cut spray application time in half. A potent blend of broad-spectrum insecticide and fungicide is key. Active ingredients can include organics like pyrethrins and neem oil, or inorganic chemicals like malathion, carbaryl, and captan.

Trees may require additional treatments. See product label for detailed instructions.

Apply micronutrient foliar sprays during cool, overcast weather at or near petal fall.

If your fruit trees are lacking in zinc, copper, magnesium, molybdenum, boron, or calcium, a foliar application of one or more of these micronutrients may help. Be careful; unnecessary or excessive application of these nutrients can damage fruit trees.

Foliar fertilizer cannot replace good soil fertility. A tree cannot absorb enough of the main nutrients it needs through the foliage.

Apply granular fertilizers in early spring.

The best time to fertilize fruit trees is in early spring. Apply a granular fertilizer such as Jobe’s Organic to the root zone as the leaf buds open. The first growth spurt in the spring comes from the energy stored in the roots. By the time the fertilizer soaks into the soil, the tree is ready to absorb the nutrients for optimal growth and fruiting.

Avoid fertilizing after mid-spring. A spike in soil nutrients during fruit development can cause trees to abort fruit to produce more vegetative growth.

when to spray fruit trees

istockphoto.com

Use combination sprays during the growing season to target both insects and disease.

Combination sprays are two different pesticides sold individually, normally an insecticide and a fungicide, mixed together in the same sprayer and applied at the same time. This practice is a way to customize an application and save time.

Not all products are compatible and some mixtures can be dangerous. Read both product labels before mixing to make sure mixing the two is safe and allowed.

Need a hand with landscaping?

Consider hiring a pro. Find trusted local landscapers and receive multiple no-obligation quotes.

+

Comments are closed.