Gonocephalum (false wireworm)

Larvae of Gonocephalum are attracted to germinating seeds. The larvae damage the seeds and the developing roots and shoots. Larvae scrape away at least part of the seed coat and feed on the kernel and cotyledons.

Adult Gonocephalum destroy emerging seedlings by feeding on the cotyledon leaves, or on the growing tip, or by 'ring barking' the stem at ground level. Even seedlings which develop a woody stem, including cotton (Robertson, 1993) and coffee transplants (Mlambo, 1983), can be killed.

Adult Gonocephalum are active on the soil surface, and tend to damage dicotyledonous crops more severely than monocots. Sorghum seedlings can withstand some feeding on emerging leaves, whereas the growing points of dicots are easily destroyed by Gonocephalum adult feeding (Robertson, 1993). Germinating cereal seeds, however, are readily destroyed by larvae of Gonocephalum.

G. macleayi is a regularly-occurring pest of cereals sown in spring and summer, oilseed sunflower, and legumes in eastern Australia. Cotton, maize, and other crops are occasionally attacked. Seedling losses can be high enough to necessitate replanting over hundreds of hectares in some years. G. macleayi often co-exists with other soil-dwelling pests, and losses can seldom be attributed to one species.G. simplex is widespread in Africa south of the Sahara, and a wide variety of crops are affected. Economic losses have not been quantified, and this pest also occurs with other soil-dwelling pests (Mlambo, 1983). Severe thinning of stands of sunflower and maize seedlings are recorded in some years in South Africa (Drinkwater, 1992). In one report from India, Gonocephalum sp. damaged 5% of pods of groundnut in Andhra Pradesh (Reddy et al., 1992). Gonocephalum spp. appear to cause sporadic damage over most of their distribution.