Outbreak of Mealy Bug in Tharaka Nithi County



Following reports of widespread outbreak of what has been identified as the devastating Mealy bugs in Tharaka Nithi County, the Department of Agriculture wishes to assure farmers  the County Government is doing everything possible to bring the unfortunate situation under control. 

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Infestation by the pest can cause up to 100% crop loss if not controlled,  therefore, it is very important to eradicate  the mealy bug that is attacking  pawpaws,  avocados, cassava, tea bushes and macadamia among other crops.

Our  agricultural officers are conducting  farm visits and plant clinics at Ndagani, Mbogoni Irrigation Gichenge offices, Kambandi agricultural office and Kirege.

Agro-dealers are also assisting farmers having been alerted to do so as farmers call on them

In collaboration with central government field barazas are ongoing on control of fall army worms (FAW) and the mealy bugs.

All agricultural offices at County, sub county and wards are open for farmers to consult.

There are several ways that can be used to manage and control this pest;

Chemical Control

To effectively control mealy bugs, the chosen insecticide should have a systemic characteristic.

The following products are therefore fit for the control of this pest;

  • EMERALD 10ml/20l of water
  • LOYALTY 5g/20l of water
  • AMAZING TOP 5g/20lwater
  • LEXUS 8ml/20lwater
  • BESTOX 10ml/20l of water

NB: Always mix the insecticide with INTEGRA 3ml/20l. or DCTronPlus. All these are found in the Agro shops in the County eg. East- End, Jufra, Farm line, Teka agro, Acandia, Sorghum Pioneer Agency.

Integra  and DCTron plus ensures that the products you spray stick  to the leaves and stem, spreads to all areas of the leaf and penetrates to the underside.

  • To cleanse the sooty mold, spray Teepol soap or any liquid detergent 50 ml/20l.of water


  • Removal of all the infested materials from the field.
  • Crop rotation with non-host plants
  • Ensuring field sanitation
  • Field borders should be free from weeds and debris that may harbor this pest.


  • Soapy water- mixed with cooking oil- e.g 1 teaspoon of vim and 1 teaspoon cookin oil in 1 litre of water.
  • Neem (Muarobaini) solution
  • Soak tobacco leaves overnight and spray the solution

Identification of the Mealy Bugs

Mealy bugs are soft bodied sucking insects with cottony appearance found under  leaves, stems, and roots in colonies and are covered with white masses. The outbreak has been triggered by prolonged dry spell and climate change characterized by change in weather patterns.

Feeding and damage

  • Mealy bugs feed on plant parts through piercing and sucking. Both nymphs and adults suck the sap causing withering and yellowing of leaves while fruits may drop prematurely. Heavy infestation can cause defoliation and even death of the plant.
  • Infested growing points become stunted and swollen. Severity of infection depends on the susceptibility of the host species.
  • Heavy clustering of mealy bugs can be seen under leaf surface giving the appearance of a thick mat with waxy secretion.
  • While feeding, they excrete copious amount of honey dew that attracts ants. The honey dew facilitates for the development of black sooty mold on leaf surfaces. This inhibits photosynthesis. Mealy bugs also affect the development of flowers and stems especially in succulents with fleshy stems.
  • Infested fruits can be entirely covered with the white, waxy coating of the mealy bug, and this can cause shriveling of the fruits.

Major Crops and plants affected:

  • Paw paws
  • Sweet Potatoes
  • Cassavas
  • Avocados


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