Integrated Pest Management of Sweet Potato

Integrated Pest Management of Sweet Potato

•      The sweet potato weevil is a serious pest in the field and in storage. It is the   most numerous close to the soil surface.

•            Eliminating weevils from planting material should begin with sanitation in and around the storage area. Malathion can be sprayed in the storage areas to kill weevils. One small, infested sweet potato can produce many weevils.

•           At harvest, all the sweet potatoes to be stored should be dusted with 5% Imidan dust.

•      The banded cucumber beetle is the most common cucumber beetle attacking sweet potatoes in Louisiana, but the spotted cucumber beetle will feed on sweet potatoes. Both species feed on several different host plants including vegetable and field crops, as well as weeds. Cucumber beetles are oblong-oval, have beaded antennae and are about ¼ inch long. 

•      Several species of white grubs are pests of sweet potatoes, but the most prevalent species is Phyllophaga ephilida. Larvae are often abundant in pasture, sod or weedy fields and can injure roots severely when sweet potatoes are planted in fields that follow pasture. Adults are active at night and feed on the leaves of deciduous trees. They emerge in late May through mid July. 

•      Whitefringed beetles can be a serious problem for growers. Whitefringed beetles have been reported on more than 385 plant species, including peanuts, corn, sugarcane, cotton, cowpea, beans, cole crops, alfalfa and sweet potatoes. Larval injury to sweet potato roots resembles that caused by white grubs. Larvae gouge out narrow, shallow to deep channels on the surface of the root. 

•      Several species of wireworms seriously injure sweet potatoes. Adults, known as click beetles, do not feed on the crop but oviposit on the soil near the crop, weeds or other vegetation. Wireworms have a very broad host range and will feed on weeds in the fields. Larvae produce small, round shallow feeding holes on the root surface. The original holes are usually less than 1/4 inch deep, but may be considerably deepened by later growth of the sweet potato root.

Disease Management

•      Some of the diseases of sweet potato crop along with the symptoms and control along with the causal organisms are described below:

Charcoal rot (Microphormina phaseoli):

Symptoms:
The infected tissue becomes chocolate brown, later on dark red or brown and ultimately black in colour. Minute black sclerotia are seen in the rotted tissues.

Control Measures:
Vines should be raised from healthy fields.

Soft rot (Rhizopus nigricans):

Symptoms: 
This cause storage rot of tubers. The tissue becomes soft and stingy.
Control Measures:
The sweet potato tubers should be stored in disinfected and clean stores. 
Black rot (Ceratocystis firmbriata, Ceratostomella firmbriata):

Symptoms:
This disease causes heavy loss in field and storage. The infected roots show dark brown or black spots. Infected vines show yellow, silky appreance of foliage. These are greyish black, circular, depressed spots on the fleshy roots.
Control Measures:

Proper sanitation should be maintained in field as well as storage