Hawkmoth 1
Namibian crop pests # 47
Agrius convolvuli
=Herse convolvuli		 Order: Lepidoptera Family: Sphingidae
 


caterpillar, brown form
  


caterpillar, brown form
 


caterpillar, pale green form
  


caterpillar, black form
 


Imago, grey form
  


Imago, dark form
 
 
 
 
 


Pupae

 

Common names: 

 None recorded

Pest status:

 The sweet potato hawkmoth (or hornmoth) is common and widespread in Northern Namibia but reports of damage are rare. Sweet potato is not common in northern Namibia yet, but damage report may become more frequent when the crop has been promoted by the research and extension services..

Description:

 Large night-flying moth with a wing span of about 8-9 cm. Wing colour may be dark grey or a mottled light grey. Note the distinct red and black lines across the back of the body. 

The caterpillar is as large as a man's finger and has a conspicous 'horn' at the rear end. There are different colour variations among the caterpillars, most are brownish others are green with stripes on the side, and a few may be nearly black. All forms are shown above.

The adult hawkmoth is attracted to strong lights and is therefore often found resting on walls near the security light early in the morning.

Control:

 Chemical control is not recommended as the species is seldom of any economic importance. If an attack should occur, the large caterpillar can be handpicked from the plants. The caterpillar may looks dramatic and dangerous but it won't sting or harm humans.

At Ondobe ARDC, they let out the chicken in the sweet potato field to eat the many caterpillars.

In the few cases where chemical control is needed, virtually any chemical will work on these soft-bodied caterpillars. Farmers mainly use Karbaryl or Malathion.
 
 
 

Other notes:

 A field of sweet potatoes was severely attacked by hawkmoth caterpillars at Epalela project along Olushandja dam, Omusati region. All sweet potato plants in a 1/4 ha field were completely defoliated and each of the bare vines carried 2-3  of the conspicous caterpillars. 

It was near time of harvest, and the field looked like a failure, but farmers later reported that there was hardly any reduction of the tuber yield. One women in the project handpicked the caterpillars and had buckets full of them. When asked, she said she used them as manure. We expect, however, that she was preparing them for eating as she took out the guts in the same way as for other caterpillars that eaten (see for instance mopane worms)

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