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Plantwise Factsheets for Farmers

Palm Thrips of Watermelon

Thrips palmi

Recognize the problem

Palm thrips are a major pest of watermelon in Grenada. They mainly attack the growing tips of the vine. The tips become brown and stop growing. This pest can destroy the entire crop if left untreated. 


Palm thrips are able to feed and survive on most of the vegetables grown. It is very important to remove and burn all crop residues and keep the plot free from weeds which serve as alternate hosts. They multiply rapidly so constant monitoring is important so that action can be taken when necessary.


  • Practice crop rotation with unrelated crops
  • Remove and burn crop residues
  • Use barriers such as corn around the plot
  • Use imidacloprid (Admire) 7-10 days after transplanting as a drench. 3-5 tsp /gal water when soil is moist.
  • Monitor for the pest and its natural enemies such as Orius bugs 4-5 weeks after drenching. If natural enemy populations are high and  are keeping the pest population under control, avoid using more insecticides
  • If infestation is high, spray pyriproxyfen (Admiral) 1-2 tsp per gallon together with acetamaprid (Caprid) (PHI 7 days), 1tsp/gallon
  • Apply nitrogen fertilizer to enable plant to recover from damage.

When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.

The recommendations in this factsheet are relevant to: Grenada

Authors: Francis Noel
Pest management Unit (MOA)
tel: 440-0019 email:
©CAB International. Published under a CC-BY-SA 4.0 licence.

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