Controlling Fruit Drop in Mango

Why Do Mangoes Drop Fruit?

Mango trees naturally shed some flowers and young fruits. This is a way for the tree to regulate its load and ensure the remaining fruits develop well. However, excessive drop is often caused by several factors:

• Nutrient Deficiency: Lack of essential nutrients like Boron, Zinc, or Potassium can weaken fruit attachment.
• Water Stress: Both too little or too much water can cause stress, leading to fruit drop. Dry spells followed by heavy rain are particularly damaging.
• Pests and Diseases: Pests like fruit flies, hoppers, and diseases like powdery mildew or anthracnose can damage flowers and young fruits, causing them to drop.
• Hormonal Imbalance: Imbalances in plant hormones, especially auxins, can lead to premature fruit shedding.
• High Temperatures and Hot Winds: Extreme weather conditions during flowering and fruit set can cause stress.
• Poor Pollination: Inadequate pollination can result in poorly formed fruits that eventually drop.

Nutrient Management for Stronger Fruit

Providing balanced nutrition is crucial for healthy fruit development and retention. Focus on both macro and micronutrients.

• Nitrogen (N): Important for vegetative growth, but excessive nitrogen can lead to more leaves and fewer fruits, or increased drop. Apply judiciously.
• Phosphorus (P) and Potassium (K): Essential for flowering, fruit set, and fruit development. Potassium, in particular, strengthens fruit attachment.
• Micronutrients: Boron and Zinc are vital. Boron helps in pollen germination and fruit set, while Zinc is important for overall tree health and hormone balance.

A typical fertilizer schedule might look like this:

Tip: Always get your soil tested to determine exact nutrient needs and avoid over-fertilization.

Proper Irrigation is Key

Water management plays a critical role in preventing fruit drop. Both water scarcity and waterlogging can stress the tree.

• Pre-flowering: Reduce irrigation slightly to induce flowering stress.
• Flowering and Fruit Set: Maintain consistent, moderate moisture. Avoid heavy irrigation during flowering as it can wash away pollen or promote vegetative growth over fruit set.
• Fruit Development: Provide regular and adequate water, especially during dry periods. Water stress at this stage is a major cause of fruit drop.
• Avoid Extremes: Do not let the soil dry out completely and then flood it. This sudden change can shock the tree and cause fruits to drop.

Drip irrigation is highly recommended as it provides water directly to the root zone efficiently and consistently.

Pest and Disease Control

Timely identification and management of pests and diseases are essential to protect developing fruits.

• Mango Hoppers: These pests suck sap from flowers and young fruits, causing them to dry and drop. Spray with insecticides like Imidacloprid or Thiamethoxam during flowering.
• Powdery Mildew: This fungal disease affects flowers and young fruits, covering them with a white powdery growth. Spray with fungicides like Sulphur or Hexaconazole.
• Anthracnose: Causes black spots on flowers, young fruits, and leaves, leading to fruit drop. Apply fungicides like Carbendazim or Mancozeb, especially before and after monsoon.
• Fruit Flies: Lay eggs in developing fruits, leading to premature drop. Use fruit fly traps and practice orchard sanitation.

Always follow recommended dosages and safety precautions when using pesticides and fungicides.

Hormonal Sprays: A Strategic Approach

Plant growth regulators (PGRs) can be used to reduce fruit drop, but they must be applied carefully and at the correct stage.

• Naphthalene Acetic Acid (NAA): This auxin helps in fruit retention. A common recommendation is to spray NAA at 10-20 ppm (parts per million) when fruits are pea-sized (about 1-2 cm in diameter).
• Gibberellic Acid (GA₃): Can also be used, sometimes in combination with NAA, to promote fruit growth and retention.

Caution: Over-application or incorrect timing of hormones can have adverse effects, including fruit malformation or thinning. Consult with local agricultural extension officers for precise recommendations for your specific mango variety and region.

Controlling fruit drop in mango requires a holistic approach. By ensuring balanced nutrition, managing water effectively, protecting trees from pests and diseases, and judiciously using growth regulators, farmers can significantly reduce fruit loss and achieve higher, more consistent yields. Regular monitoring of the orchard is key to early detection and timely intervention.