Assessment of the damages on maize crop by the invasive stink bugs Halyomorpha halys (Stål, 1855) and Nezara viridula (Linnaeus, 1758) (Hemiptera: Pentatomidae).
Recently, the brown marmorated stink bug, Halyomorpha halys, and the southern green stink bug, Nezara viridula, two invasive, highly polyphagous species, have caused huge damages on many crops, including fruits, vegetables, soybean, wheat and field maize, both in the USA and Europe. The two stink bugs rest on the maize ears and feed through the husk, by penetrating with their rostrum each kernel and sucking its content, leaving the maize kernels discoloured and shrunken, with mottled appearance. Early attacks lead to deformations of the maize cobs. Observations made on six maize hybrids in maize fields in southern Romania, in 2016, revealed 23-29% attacked kernels in non-irrigated fields and almost 37% attacked kernels in irrigated fields, under the pressure of maximum 16 adults/plant. The starch content decreased by 20-22%, with no significant differences between hybrids. The statistical analysis of protein content reduction indicated that the hybrids may have a different reaction to stink bugs feeding.