ICIPE: Managu 'kills' crop mites

Hairy_nightshade_Solanum_sarrachoides_13Ontario_04.JPG

Farmers can control red mites attack on vegetables by growing the hairy African nightshade, commonly called managu, along orchard borders after a research revealed that the crop terminates the reproduction cycle of the pest.

Red mite susceptible crops include gooseberry, bitter apple, tomato, eggplant potato, among others.

International Centre for Insect Physiology and Ecology (ICIPE) researcher Dr Lucy Kananu said the hairy variety, scientifically known as Solanum sarrachoides, secretes chemicals that prevent the red tomato spider mites from laying eggs.

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The managu leaves have a sweet scent that attracts the pests. After landing, the same leaves release an odour that interferes with the reproduction, therefore, terminating the pest.

“When the mites reach the leaf’s surface, the ‘small hairs’, scientifically known as trichomes, trap the pests, hence hindering further movement.”

“Additionally, the disturbance caused by the mites on the leaf surface triggers the glandular tips, or the ‘succulent lobes’, of these hairs, to crack. The cracked lobes then release secretions that contain foul smelling chemicals that prevent the pests from laying eggs, thereby breaking their reproduction cycle,” Dr Kananu, the lead author of the study said.

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The researcher said mites can destroy up to 80 per cent of the crop. The destruction can be 100 per cent during hot weather when reproduction of the pests is high.

In protecting other susceptible crops in the Solanaceae family, Dr Kananu advocates growing the hairy nightshade along the border or around the crop of interest to act as a death trap for the mites.

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This is one of the practical methods of controlling pests as the consumers, especially international markets, drift toward organic farming dues to risks associated with chemical pesticide residues. 

Prof Baldwyn Torto, who supervised the ICIPE research, said the discovery is a key step in uncovering more environmental friendly ways of managing the pest in crop production.

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PHOTO: A picture of an African nightshade. ICIPE has discovered that the variety can protect other crops against the destructive red mites. PHOTO BY Oregon State University.