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Annals of Sri Lanka Department of Agriculture 2019. 21 3

**The full paper of this article will be published in the Tropical Agriculturist Vol: 167 of 2019

Biology and management of Harpedona marginata Distant

(Hemiptera: Miridae): A pest of Dioscorea species in Sri Lanka

P.H. Ranaweera1

, S. Rathnamalala2

, S. Nanayakkara1

, M. Ranathunga1

and

D. Galanihe3

1Horticultural crops Research and Development Institute, Gannoruwa, Sri Lanka

2

In-service Training Institute, Gannoruwa, Sri Lanka

3Rice Research Institute, Batalagoda, Sri Lanka

Abstract

Harpedona marginata Distant (Hemiptera: Miridae) is an emerging pest in

Dioscorea cultivations in Sri Lanka. Pest damages were observed in July to September

2017/2018. Thirty three Dioscorea accessions were evaluated at Horticultural

Crops Research and Development Institute (HORDI), Gannoruwa and all evaluated

accessions were susceptible for this pest. The study was focused on morphological

characterization, information on life cycle and chemical control measures of the pest.

Male and female insects are morphologically very similar. Head and body have black,

3- 4 mm in length. White colour patches were found on infested leaves. In severe

infestation, leaves become brownish colour. H. marginata took 26.0 ± 0.47 days

to complete its life cycle at 27 0C. Potential insecticides to control H. marginata in

laboratory bioassay were 0.75% Neem formulation 5 ml/l (Lakgro neem), Neem seed

water extract (30 g/l), Thiamethoxam 25% WG, 0.5 g/l (Actara), Imidacloprid 20%

SL, 1 ml/l (Admire) and Thiamethoxam 25% WG + Cloranthraniliprole 20%SC 0.25

g/l (Vertako). Thiamethoxam 25% WG and 0.75% Neem formulations were shown

positive results in controlling both adults and nymphal stages of H. marginata in field

screening.

Key words: Life Cycle, Morphology, Neem