Apple farming in Kenya has gained significant attention due to its economic potential and the rising demand for locally produced fruit. However, achieving a successful apple harvest requires careful planning and the implementation of effective fertilizer and spray programs. In this guide, we’ll walk you through the essential steps to optimize your apple farming practices in Kenya.

A Comprehensive Guide to Fertilizer and Spray Programs for Successful Apple Farming in Kenya

Many factors, in addition to soil tests and fertilizer application rates affect the nutrition of apples and most other deciduous fruit tree species. Some varieties respond differently than others. Additional factors include rootstock, dwarfism, subsoil physical and chemical condition, and others. The intended use of the fruit is sometimes an additional factor in determining the proper fertilizer program. While soil testing is an indispensable tool in orchard management, Annual leaf analysis (in addition to periodic topsoil and subsoil testing) is required to properly manage the crop nutrition.

Maintaining a thriving apple orchard goes beyond the traditional practices of fertilization and spraying. It involves a comprehensive strategy that starts with good care and management.

1. Sanitation and Clean-Up:

Proper sanitation is the foundation of a healthy orchard. Regularly clean up fallen fruit and leaves to eliminate potential sources of infection. This practice prevents the overwintering of pests and diseases, ensuring a clean slate for the upcoming growing season.

2. Weed Management:

Reduce weed growth around the trees to eliminate breeding, feeding, and overwintering sites for pests. A weed-free zone contributes to better orchard hygiene, minimizing the risks of pest infestations and disease spread.

3. Pruning for Canopy Health:

Good pruning is a fundamental aspect of orchard care. By removing diseased wood, you not only eliminate potential sources of infection but also promote better airflow through the canopy. Improved air circulation reduces the population of insects and disease-causing organisms, contributing to a healthier orchard ecosystem.

4. Disease-Resistant Cultivar Selection:

Choose apple cultivars known for their resistance to common diseases. This proactive approach reduces the reliance on chemical interventions and contributes to the long-term sustainability of the orchard.

5. Mulching and Soil Conditions:

Mulch around the base of trees to retain soil moisture, suppress weeds, and regulate soil temperature. Plant trees in well-drained, moist soil conditions to ensure optimal root health and nutrient absorption.

6. Appropriate Watering:

Provide adequate water, especially during dry periods, to support the growth of young trees. Proper hydration is crucial for establishing strong root systems and promoting overall tree vitality.

Traps for Monitoring and Control:

Incorporate traps strategically into your orchard management plan. Sticky traps, designed for specific pests like codling moths and apple maggot flies, serve as effective monitoring tools. Regularly check traps to assess pest presence and population size, allowing for timely decision-making regarding the need for targeted interventions.

Spray Schedule for Apples

Good culture practices and sanitation may not be enough, and apple trees may need to be sprayed to prevent common insect pests like apple maggot and coddling moth and common diseases like apple scab, powdery mildew, cedar apple rust, and fire blight.

Applying the Spray

Whenever sprays are applied, it is important to follow label directions. The most effective control comes from applying the product as directed. Nearly all spray treatments will require multiple applications spaced throughout the growing season. The interval between spray applications should be strictly followed.

When applying the spray, utilize a pump sprayer and thoroughly cover all the foliage and branches. Never mix more spray material than needed for that application and always store chemicals in their original containers.

When applying the spray, wear appropriate personal protective equipment as outlined on the label. This usually includes long sleeves and pants, goggles, and chemical-resistant gloves. Always apply chemicals when winds are calm (less than 10 mph), temperatures are cool but above freezing, and no rain is forecasted for at least six hours. More details on appropriate weather conditions for specific chemicals are listed on the label.

Timing of the Spray & Developmental Stages

The timing of the application is important as many insect pests are more susceptible to sprays at certain points in their life cycle, and most diseases are best controlled preventively before the symptoms are observed. Often the product label will direct the farmer to spray at certain developmental stages in the tree’s annual growth cycle. The precise time of year these stages are observed will vary year to year by location, climate, and weather conditions.

Developmental Stages of Apple

Below are the key developmental stages to know and what those stages look like on an apple tree.

StageWhat it Looks LikeInsects & Diseases Often Controlled at this Stage
DormantDormantBuds are small and tight, no signs of growthscale, aphids, spider mites
Silver TipSilver TipBuds swell and turn fuzzy silver from emerging leavesaphids, scale, mites, apple scab
Green TipGreen TipGreen leaves begin to emerge from the tips of budsapple scab
Half-inch GreenHalf-inch Green (Mouse Ears)One half-inch of leaves are visible, folding backward as they emerge, resembling small mouse earsapple scab
Tight ClusterTight ClusterYoung apple leaves have emerged and are folded backward, revealing a tight flower clusterapple scab, powdery mildew
PinkPink BudFlower buds have grown to reveal pink petal color but still not openapple scab, powdery mildew, plum curculio, apple sawfly
King BloomFirst (King) BloomThe center (or king) bloom opens first, before the buds that surround itapple scab, powdery mildew
Full Bloom At least 80% of the flowers are openapple scab, powdery mildew, cedar apple rust
Petal FallPetals are raining down from trees, carpeting the groundapple scab, powdery mildew, cedar apple rust, plum curculio, apple sawfly
Fruit SetYoung fruit is visibleapple scab, powdery mildew, plum curculio, apple sawfly

Protecting Pollinators

Most insecticides are toxic to all insects, including important pollinators like bees. Insecticides, both organic and synthetic, applied while bees are active (such as during full bloom) can negatively impact these beneficial insects. Avoid spraying plants when pollinators are visiting the tree. Use systemic insecticides with caution as the insecticide may be present in the pollen and nectar of the trees if growing in a treated area. The “Environmental Hazards” section of the insecticide label will outline the important precautions that should be taken when bees are present.

Organic Spray Schedule for Apple

This approach utilizes organic sprays to help control the most significant insect and disease issues, including apple maggot, codling moth, apple scab, and powdery mildew. It is one example of an approach that can be used. Additional control strategies may be needed. Always follow label directions on any chemical spray, even if it differs from what is listed below.

StageSpray
DormantDormant oil for scale and overwintering eggs of aphids and mites, control of some diseases
Silver TipCopper for fire blight
Green TipSulfur (must be three or more weeks from dormant oil) for disease prevention; insecticidal soap or neem oil for aphids and mites (if a problem)
Pink BudSulfur spray (not lime sulfur) for disease prevention; neem oil for aphids (if a problem); Bt or spinosad for pest caterpillars (do not mix with sulfur spray; apply separately)
First BloomDo not use other insecticides at this time to avoid harm to beneficial pollinators such as bees
Petal FallRepeat sulfur and Bt or spinosad and again 7-10 days later, if needed, or begin kaolin clay sprays for insect pest control
Fruit Set & Throughout SummerStarting at this stage spray sulfur spray or potassium bicarbonate every 7-14 days when signs of disease are observed, stop 30 days before expected harvest; spray pyrethrum, spinosad, insecticidal soap, or neem when any insect pests are observed on the same schedule

Home Orchard Sprays

For many home gardeners, a home orchard spray is the most straightforward management option. They are often the best place to start when you are looking to start a pest and disease management plan.  These mixtures typically contain one or more insecticides, such as carbaryl, permethrin, or malathion, and one or more fungicides, typically captan or sulfur. They are formulated to control common apple pest insects and diseases such as apple maggot, coddling moth, apple scab, powdery mildew, and cedar apple rust. Always check the label to be sure they are safe to use on apples and control the insect or disease issues you have the most problems with.

Read the entire label and follow the spray schedule outlined on the label.  For the best control, it is important to follow the directions closely applying the spray at the correct rate and time throughout the entire growing season.

Home orchard sprays greatly simplify the spraying process, but they have a few limitations.  They can lead to applying a spray when one of the pesticides in the mix has no benefit to the crop. The result is that these pesticides are wasted and depending on when they are applied could cause problems for beneficial insects or pollinators. Always read the label carefully and thoroughly, and be sure to apply the home orchard spray when bees are not active, such as before or after the bloom period or at dawn or dusk when they are less active.

Non-organic Spray Schedule for Apple

If you choose not to use a home orchard spray, then pesticides will have to be purchased and applied separately in accordance with each product’s label.
The spring spray schedule below utilizes “traditional” non-organic sprays to help control most insect and disease issues. It is one example of an approach that can be used. Additional control strategies may be needed. Always follow label directions on any chemical spray, even if it differs from what is listed below.

StageSpray
DormantDormant oil for scale and overwintering eggs of aphids, mites; control of some diseases
Green TipMancozeb for rust (must be three or more weeks from dormant oil)
Tight ClusterCaptan or mancozeb for scab and rust
Pink BudCaptan or mancozeb for scab; malathion for sawfly;  Bt for pest caterpillars
First BloomCaptan or mancozeb for scab (do not use other insecticides at this time to avoid harm to beneficial pollinators such as bees)
Petal FallCaptan or mancozeb for scab; carbaryl, malathion, or indoxacarb for plum curculio
Fruit Set & Throughout SummerCarbaryl, malathion, or indoxacarb for plum curculio;

 

Starting at this stage, spray captan or sulfur every 10-14 days for scab, stop 30 days before expected harvest; spray carbaryl, malathion, indoxacarb, acetamiprid, or spinetoram for apple maggot and codling moth on the same schedule.

 

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