Uganda attacked by the sweet potato butterfly caterpillar

Have you ever heard of the sweet potato butterfly caterpillar?

Uganda has been attacked by the sweet potato butterfly caterpillar (acraea acerata) which attacks sweet potato vines.  The State Minister for Agriculture Henry Bagiire has distributed over 200 spray pumps to 9 districts that are affected with the outbreak of sweet potato butterfly caterpillars in a bid to control its spread. The districts include, Luuka, Iganga, Pallisa ,Bugiri ,Jinja Kamuli,Bukedea ,Budaka and Namutumba.

The Minister and Mr. Stephen Byantwale the Commissioner for Crop Inspection are visiting the districts informing the public about the best ways of controlling the Sweet Potato Butterfly Caterpillar.

The State Minister for Agriculture Henry Bagiire

A. acerata is a production limitation in some localities of Eastern Africa. Outbreaks are irregular and seasonal and usually occur at the beginning of the dry season. Complete defoliation and/or repeated defoliation results in reduced production. The caterpillars feed on the leaves of sweet potato plants , generally working from the edge inward, and leaving only the midrib and main veins sometimes  completely destroying the plant.

Young caterpillars hatch in large groups inside a nest formed of several leaves joined with a web.  They feed on the upper leaf surface, and the leaves of the nest become brown and dried-up and covered with their excrement.  Older larvae become solitary and feed at night, usually remaining on the soil during daylight.

Egg      The pale-yellow eggs measure about 0.5 mm wide and 0.7 mm long, and are laid on the leaf surface in groups of several hundred.

Larva    The mature larvae are greenish-black and covered with fleshy, branching spikes.       Caterpillars reach a size of 20-24 mm before pupating.

Pupa    The pupae are cream to blackish with brownish banding on the back, and measure 12-15 mm.

Adult The adult sweet potato butterfly has orange wings with brown margins.  Wingspan is 30-40 mm.

 A. acerata is found in all zones of sweet potato production in Eastern Africa, but is considered a constraint in relatively dry agroecological zones. Outbreaks are common in Rwanda.

Females lay eggs in batches of 70 to 500 eggs on both surfaces of the leaves. Development is temperature-dependent. The egg stage takes 5 to 10 days.  The larva passes through five larval stages in 16 to 26 days. The larvae are concentrated in a protective webbing for the first 2 weeks after hatching. They then become solitary and hide from the sunlight on the ground during the day. For pupation the caterpillars crawl up the plant or any convenient support, such as tall grass or a wall bordering the sweet potato field. Here the pupa is suspended in a vertical position. The pupal stage takes 4 to 10 days.

The Minister distributing spray pumps


Mechanical control – The traditional method of controlling outbreaks has been to handpick and destroy nests of young caterpillars. A limiting factor might be lack of labour.

Chemical control – Severe outbreaks might warrant the use of contact insecticides.

Cultural control – Intercropping sweet potato with onion and/or the silverleaf desmodium, Desmodium uncinatum, might reduce the number of eggs laid by the females on sweet potato. 

Share your views about this story

Related stories

Traders charged with smuggling 350 bags of maize into Kenya

Three businessmen have been charged before Busia Law courts Senior Principal Magistrate Hon. Phoebe Kulecho with counts relating to smuggling of 350 bags of maize worth Kshs 800,000 in taxes. Joseph Kiprono  and Mugisha Moses  were charged both jointly while Issa Abuneri Ingati separately faced similar charges of being in possession of uncustomed goods contrary to section 200(d)iii as read with section 210 and 211 of the EACCMA,2004 and that of conveying uncustomed goods contrary to section 199 (b) as read with section 199(c|) EACCMA,2004. Joseph and Mugisha were intercepted by Adungosi Police Station Officers while transporting 200 bags of uncustomed maize worth Kshs 460,000 in taxes on 9th March this year at Among’ura- Amaase Murram road Teso South within Busia County. The accused persons denied the offences and were each released on bond of Kshs 200,000 or bail of Kshs 100,000. Their case will be heard on 6th May 2021 and mention on the 25th March 2021.

Read more »

Subscribe to Kilimo News

Get the latest agriculture news in East Africa