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About 20 species of insect pests has been reported to attack the custard apple (Butani, 1979), of which the mealy bug species viz., Striped mealy bug – Ferrisiavirgata (Cockerell), Pink mealy bug – Maconellicoccushirstus (Green), Citrus mealy bug – Planococcuscitri (Risso), Passion vine mealy bug – Planococcuspacificus Cox (Hemiptera: Pseudococcidae) and Mango mealy bug, Perissopneumonferox are the major one causing significant fruit yield loss.
What is mealy bug?
It is the insects which suck the cell sap from the leaves flowers fruits and succulent plant parts hampering and destroying the growth of plant.
Life cycle of Mealy bug
Eggs – The eggs are laid as egg sacs in mass of wax threads in loose soil between April and May. The colour of the eggs is purple and eggs period is 23-28 days.
Nymphs – Eggs are generally hatch in December to January and travel to the tree via stem or fruits that touches the soil surface and feed on cell sap. The nymphs are yellow to pale white in colour and the total nymph period is 21-29 days.
Adults – The adult males are winged and short live after mating and cause no harm to the crops while adult female suck cell sap and crawl down to the ground for egg lying. The life of male and female adult is 12-31 days.
How does it damage the fruit?
- Both nymph and adults suck sap from the leaves causing withering and yellowing of leaves.
- Sometimes fruit may be drop prematurely and cause defoliation too.
- Heavy infestation may lead to sooty mold i.e. fungal infection also attracts black ants which help in the spread of these mealy bugs.
- Mealy bugs secrete honey dew which causes the secondary infestation of sooty mold which inhibits photosynthetic efficiency of the plant.
Symptoms
- Appearance of thick mat with waxy secretion in heavy infestation and it resembles the patches of cotton all over the plant.
- It infests at fruit stalks, leaves and terminal shoots causing, yellowing and drying symptoms.
How to manage or control the mealy bug?
Mealy bug found to be more active in dry weather condition or often it is mostly incidence occurs in prolonged drought. The heavy infestation up to 40-80% occurs during November (Kapadia et al., 2009).
Cultural control
- Collection and destruction of all infested plant parts such as leaves, peduncle, twigs and fruits.
- Racking of soil around the tree region to expose the eggs of bugs and repeat after one-month upto75 cm depth.
Mechanical control
- Pruned the affected area and remove the debris from the orchard.
- Equipment’s should be sanitized before moving to uninfected portions in a crop.
- Mealy bug control often involves the control of caretaking ants that are important for the proper development of mealy bugs. Without the ants, mealy bug populations are small and slow to invade new areas and the field would be free of a serious mealy bug infestation. Therefore, management of mealy bugs often includes the control of ant species.
- Apply sticky bands on main stem to prevent crawlers of mealy bugs reaching the bunch.
Biological control –
- Apply neem oil 5ml of water along with detergent 1gm per liter of water omn infected parts.
- Release of Cryptoleamus montrouzieri (ladybird beetle) @ 10 numbers per tree would be effective to predate upon the eggs and nymphs of the mealy bugs. (Mani and Krishnamoorthy, 2007).
- Spray biopesticides viz., Verticillium lecanii10gm per lit and Beauveriabassiana 10ml per lit.
Chemical control –
- Application of foliar sprays of Imidacloprid (Confidor) @ 0.5ml per lit at 14 days interval.
- Apply a maximum of two foliar applications of Sulfoxaflor (Transform) during heavy infestation @ 0.5 ml per lit of water at 14 days interval.
- If ants are properly managed, population of scales and mealy bugs get reduced by 80 %. Ants move pests around on the trees, but more importantly prevent natural parasites and predators from controlling pests.
- Fipronil can be used for chemical spray to control the ants in custard apple.
