Mealybug on Hibiscus (Gurhal)

Name of the host: China rose (Hibiscus rosa-sinensis L.)
Name of the pathogen: Maconellicoccus hirsutus (mealybug)

Symptoms and Insect

Hibiscus mealybugs Hibiscus mealybugs
Colony of mealybugs Mealybugs on twig (enlarged)

Mealybugs are seen in feeding-colonies protected in the crown of foliage. Usually they thrive in the axils of leaves, branches and young developing leaves. They also thrive at both surface of leaves. They appear white in color. Humidity and warm temperature favor the mealybugs. They produce honeydews which feed the black sooty-mold. Infestation of mealybugs affect the shoot growth. Leaves are malformed and branch is stunted.
Mealybugs (Maconellicoccus hirsutus Green) belong to the family Pseudococcidae of Hemiptera. Insects are distinctly segmented, oval, soft and covered with wax. Mealybugs are most devastating piercing and sap-sucking plant pests. They suck liquids from the phloem through their long slender mouthparts. They affect many plants including rose, vegetable, fruits and ornamental plants.


Control measures

  • Smaller population can be controlled by rubbing with cotton dipped in rubbing alcohol.
  • Mealybug population can be effectively controlled by spray Carbosulfan and mixture with either Bifenthrin or Imidacloprid (Fatima et al., 2016). Adequate moisture should be maintained in soil while insecticidal application.
  • Another best chemical to get ride of mealybugs is to spray the porfenophos 40 % + cypermethrin 4 % EC (personal observation).
  • Biological control with Garden ladybugs is effective. They eat the mealybugs.

References

  • Fatima, S., Hussain, M., Shafqat, S., Faheem Malik, M., Abbas, Z. and Noureen, N., 2016. Laboratory Evaluation of Different Insecticides against Hibiscus Mealybug, Maconellicoccus hirsutus (Hemiptera: Pseudococcidae). Scientifica, 2016.