INTRODUCTION: Mango Stem Borer
The Mango Stem Borer scientifically known as Batocera rufomaculata is a very serious pest of mango. The harmful stage is caterpillar. The caterpillar of this pest is known as grub. It can be seen attacking mango tree in all mango growing regions. This pest is mainly found in South Asia, East Africa and Central America. This pest has a wide distribution range in India. Pest occurrence is common in north-western parts of India.
|Common Name||Mango Stem Borer, Tropical Fig Borer|
|Hindi Name||आम का तना बेधक (Aam ka tana bedhak)|
|Scientific Name||Batocera rufomaculata DeGeer|
|Stage||Caterpillar Stage of the Moth|
|Major Host Plant/Tree||Mango|
|Other Hosts||Drum stick, guava, jackfruit, jamun, pomegranate, papaya, walnut and sal or saal tree etc. (Ref. 01)|
Fully grown larva is yellow-white and fleshy. Length is up to 5 – 6 cm. The head of the larvae is pale-yellow in colour.
The adult of this insect is known as Beetle. It is a big and very strong beetle.
Major Identification Mark: Two long horns (antennae) equal to body length. Pronotum has two crescent yellow spots.
Colour: Pale greyish colour. Presence of yellowish spots on elytra.
2. Life Cycle
Its life cycle start with the beginning of Monsoon. Female deposits eggs inside the bark of main trunk and branches. After hatching, grubs feed on woody tissue using strong biting mouthparts.
Winter is passed in the grub stage in holes.
Again, feeding is started by the grubs. The full grown larvae make holes for pupation.
Hence, life cycle is prolonged. And, it can take 1 – 2 years.
3. Damage Symptoms
The young tree will not die suddenly. The external symptoms of attack are not always visible.
- The entire portion of a Leaf starts turn into pale yellow.
- Leaves start drying.
- Leaves wouldn’t fall just after yellowing or drying without any outer force.
- The fruits of a bearing tree show the symptoms of fruit rot.
Also Read: Citrus Disease and Pests
Inflorescence or flowers of a young tree are less affected because major incidence doesn’t occur during flowering season. The incidence occur during fruit maturity period i.e., onset of Monsoon in India.
Fruits start to rot very fast due to the lack of supplement of food. All fruits start rotting at the same time. Fallen fruits can be seen on the surface of soil at morning.
Leaves of all stages are affected. Young leaves start drying while the old leaves turn somewhat yellow before drying.
Mango Shoot: Drying of Terminal Shoots
Moisture inside the twigs dries up. Twig become wrinkled. Dried twigs can be seen bearing dried leaves.
Branches of The Tree
Main branches can be attacked by this pest. Size of branch determines the incidence of the pest. Small branches are rarely attacked. Main or big branches are attacked. The junction of branches are main point where pest incidence can be seen.
Trunk of The Tree
The tree trunk is the centre object. The affected trunk has tunnels made by the larvae. These tunnels are filled with the Husks. Husky appearance inside the bark is result of damage done by the insect eating bark’s live-matters.
Also Read: Stored Grain Pests
Nature of Damage
Major incidence of this pest can be seen on young tree of 10 – 15 years old and old and diseased tree.
- Grubs bore into main trunk making hole (See in image below).
- The whole part of a trunk can be damaged (i.e., from soil surface to top of the tree trunk) by the pest (See in image below)
- Main branches are also attacked by the pest (See in image)
Less infestation is seen on branches..
- Infestation at junction of branches is common (See in image)
The caterpillar rest inside bark (tunnels) during day time. They come out during night time to cause further damage.
Branches should be cut and destroyed.
Remove frass near the holes on main stem. Inject any organophosphate such as monocrotophos 36 WSC.
Use carbaryl 50wp.
Use kerosene oil.
Also Read: Role of Semiochemicals in Pest Management.
Elytra is forewing found in beetles.
Grub is a form of larva. It is juvenile stage of an adult beetle. A larva has to go through Transformation (Metamorphosis) Stage to become a beetle.
6. Frequently Asked Questions
Question 01. Apart from mango, which fruit plant/tree is attacked by the pest?
Answer: Apart from mango the pest species also attack important fruit plants such as Jamun and guava.
Question 02. Which variety of mango is vulnerable?
Answer: All varieties of mango are vulnerable to this pest. So, the proper management practice should be followed.
Question 03. How damageable this pest is?
Answer: This pest is deadly to mango plant/tree. Without proper management and care a plant can die easily.
Question 04. How danger this pest is for other trees of the same orchard?
Answer: The moth (adult female) can infest many trees of an orchard. Severe infestation can cause significant loss or the loss of entire orchard (young orchard) due to poor management practice.
7. Image Gallery
01. Singh et. al, 2001.
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