Issue of Flower Dropping and decreased Fruit Set in Papaya ,Management Strategies
Papaya [Carica papaya] plants or trees may be categorized to male, female or hermaphrodite trees based on type of flowers they produce. As indicated above depending on the tree's type or gender, the flowers and fruit (if found) vary in appearance, function and size. Typically, a papaya plant’s gender may change depending on the temperature during the developmental stages.
Papaya Trees – Male type
Male papaya trees’ flowers are clusters of thin tube like flowers that grow at the distal end of long stalks. In male flowers both male organ [stamen] and pistil [female organ] are present in the flowers.
In male plant flowers female organ pistil won’t function and fruits cannot be produced by the tree. Sometimes the papaya tree temporarily changes gender when temperatures rise in growing environment usually in high summers. Here the pistil may become functional and a male tree turns to hermaphrodite the tree can now be able to pollinate and produce fruit.
Papaya Trees – Female type
Female papaya trees flowers grow in small clusters or as single flowers and usually bigger than male flowers on shorter stalks. The pistil on pollination produces fruit even though the male organ stamen is not present. Fruit from pollinated flower may be green-skinned melon-type fruit with 6-15 inches long with yellow or orange flesh and black seeds. The Female type trees may produce seedless fruit when pollination has not happened.
Papaya Trees –Hermaphrodite type
Hermaphrodite tree type papaya plant produces flowers with a stamen and pistil, the male and female organs in single flower. Hermaphrodite trees have capacity to produce fruits without pollination. Hermaphrodite papaya trees may behave as male trees during hot weather and as female trees when timed or trained.
Possible Causes of Flower Drop
- Temperature and relative humidity [RH] the environmental temperature and RH especially micro climate near and around flowers must be in range of 200C to 330C and 70 % to 85 % respectively. Lesser and higher than the range affects the pollination, fertilization of papaya fruits and flowers may drop off with forming to the fruit. Chemical growth regulators can sometimes help overcome low temperature effect but the fruit developed will be seedless or may be of poor quality
- Cultural - lack or excess of nitrogen [N] fertility. Low and high dose of nitrogen may cause flower drop. The toxicity may be the direct effect for flower abortion. Ammoniacal nitrogen at even medium level has got indirect effect on flower setting and fruit setting. Indirectly ammoniacal nitrogen triggers the regular viral infections which may also result in flower dropping. Manganese micro-nutrient spray on high nitrogen doses may manage viral infections on papaya plants.
- Lack of water and excessive moisture may affect the flower development, pollination, fertilization and fruit setting. Uneven water supply to the papaya plants/ trees induces stress leading to uneven flowering and fruit setting.
- Reduced or extended light exposure has adverse effect and may affect the flower development, pollination, fertilization and fruit setting.
- Excessive wind naturally causes physical damage and pollens to swipe off leading to poor pollination and fertilization.
a) Foliar diseases Fungal infections like Powdery mildew, Downy mildew, Black spot; bacterial infections like bacterial spot, speck disease and viral infections like Papaya Ring spot infections, Curl leaf viral infections etc.
- Nutrient deficiency especially with micronutrients like Boron and Calcium in case of sandy and light soils with poor water and nutrient holding capacities.
Temperature and Relative Humidity factors are usually out of the grower’s control. A light exposure of the trees is also beyond practically supplying. Sometimes the only thing a grower can wait for favorable weather conditions and by regulating the irrigation practices at extreme conditions may help regulate the micro climatical conditions. To protect the papaya plants form high winds the physical wind barriers may be made all along the borders without affecting the required air to pass.
The controllable things possible practically, the disease and pest management may be monitored for avoiding the flower drop and get maximum yield. Proper balanced nutrient management may also help to get good flower health and better fruit setting in papaya crop.
Check out for moisture in soil and atmosphere; temperature extremities and also go for the two sprays to keep away the diseases [Powdery, Downy, Spot diseases, Bacterial diseases..etc] and also supplement the required nutrients for proper flower and fruit setting.
Combination 1
Blue copper 2 gm/L + Crystocyclin 6gm/50L + Magnum Mn 0.5 gm/L + V Zyme- 2 mL/L + Tapas sticking agent1 mL/L
Combination 2
Ridomil gold2 gm/L + Confidence 0.5 mL/L + Allbor 20% 1 gm/L + Neem oil 1 mL/L
Combination 3
Safex achook 2 gm/L + Thiamethoxam 0.5 gm/L + Tapas Bio NPK 2 mL/L + Econeem plus 1% 1 mL/L
Above sprays may be sprayed for the control of flower dropping or abortion. The combinations will control sucking pests like thrips, aphids; powdery, downy mildew and other fungal & Bacterial diseases; also supplement some essential nutrients for better flower initiation and fruit setting and avoid flower or fruit droppings.
Created by:
Vanitha k
Subject Matter Expert
BigHaat Agro PVT.
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