IPM for Sugarcane Longhorn Beetle
Dorysthenes (Lophosternus) buqueti Guerin)
Suwat Phoonphan
The insect is in family Coleoptera. The life cycle is composed of egg stage about 11-27 days, 8 instars of larvae 1-2 years, pupae 9-16 days and the adult stage for 7-20 days. The outbreak was due to drought and bad soil condition. In 2015-16 the planting cane areas are in very dry condition due to very small amount of rainfall. The yield loss is more than 60% because of drought and the insect together. In plant cane the insect causes 13-43% yield loss and 11-46% sugar loss, and in ratoon cane 54 and 57 % loss in cane and sugar yield respectively.
There are 2 types of worm, 1 year and 2 years worm, those are look the same in size and shape. The worms eat the cane inside the stalk, the plant then become dry and fall off. The worm can eat cane all growth stages. The symptom in young cane, tillering stage, some tiller may die because the worm eat its main stem.
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| Life cycle | pupae | adults |
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| Symptom in the tillering stage | At cutting stage, cane showed symptom of damage | When the cane were cut we can see hole in the stubble. If there are more than 2 holes in one meter the control measure must be done. |
Control strategies
- Mechanical control
At land preparation before planting, the field should be ploughed more than once and hand collecting larvae should be done to minimize the adults lying eggs. Crop rotation, planting green manure may be applicable. When first rain come around May to June, the adults will come out of the ground. Pitfall traps should be done to collect the beetles. Hand collecting is again should be done.
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| Hand collecting worms | worms hide in old stubbles |
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| Pitfall trap | hand collecting adults at night during 6-8 pm. |
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| female adult with 40-400 egg/ beetle | |
- Biological control
Metarhizium anisopliae infected worms found in high fertility soil. Ten kilogram of the fungus cultivated in maize media per one rai (60km/ha.) is recommended when the soil condition is suitable.
3. Chemical control Fipronil is only available chemical now.
Fipronil (Ascend 5% SC) at 80 cc. / 20L. Or 320 cc. / rai or Fipronil (Regent 0.3% G) 6 kg. / rai at planting time.
In ratoon crop special machine is required to apply chemical close to the worm (inside stubble), the machine will cut half the stubble and put the chemical in the stubble.
To keep balance of the insect, one method is to promote people eating worms and beetles menu which is successful in the northeastern part of Thailand. The taste is amazing.
