Impact of spider mite feeding on vegetable crops

Abstract

Agriculture plays an important role to determine the economy of Kerala. Being primarily an agricultural
state, contribution of Kerala to the vegetable crop industry is a crucial one. However, despite the rich diversity of
our vegetable crops, knowledge on their faunal composition, particularly of spider mites as pests and other related
details remains very much limited. In recent years due to random use of chlorinated hydrocarbons for control of
general pests, which in turn kill their natural enemies, and because of using high yielding varieties and improved
agricultural practices, many mite species which were of less importance or of no value at all during the past have
assumed the status of major pests. These, among other factors have further aggravated the situation of the problem
of spider mites as pests.
The plant feeding mites (Acari: Tetranychidae) has piercing and sucking type of mouth parts with which
it pierces the leaf tissue and sucks the plant sap. The point of suction is marked by the appearance of white spots
which gradually coalesce to form chlorotic patches, necrotic patches etc. Spider mite feeding cause various types
of direct damage like loss of chlorophyll, appearance of striplings or bronzing of foliage, stunting of growth,
formation of galls and erineal patches thereby causing an array of deformities and reduction of yield. The intensity
of damage ranging from simple mechanical injury to complex physiological alterations of the plant tissues would
lead to collapse of the photosynthetic machinery of the plant. Apart from direct damages, many are known to act
as vectors of plant viral diseases causing more potential loss to growers. In many instances, lack of information
about the correct identity of spider mites, their biology and ecology caused serious consequences to agriculture.
In view of their importance in agriculture, the present study is thought to be highly warranted, as it is
envisaged with a view to provide information on the impact of feeding of the spider mites