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Pest Status
Background
Biological Control
Chapter 34 155
Convolvulus arvensis L., Field Bindweed
(Convolvulaceae)
M.G. MAW
Field bindweed. Convolvulus arvensis L.. a deep rooted perennial of Eurasian origin. is
a serious problem in many areas and has been classed as the worst weed of the prairie
and the Great Plains States (Bakke et al. 1939). It is a serious weed in Ontario and
Quebec. especially in corn. and although it is of less importance in the western provinces
some local areas are badly infested.
Losses from bindweed competition vary with the crop and cultural methods. Rye
yields may be reduced by 20% while grain sorghum yields may be reduced by 78% . On
bindweed free land, wheat. barley. and oats yielded respectively 350.576. and 515 kg per
ha more than on infested fields (Wiese & Phillips 1976). Fast growing crops that shade
the ground may compete effectively with the weed. and winter wheat on the drier parts
of the Great Plains is a good competitor because winter and spring growth occurs when
bindweed is dormant. Summer crops may however be severely stunted or even killed by
severe bindweed competition (Weise & Phillips 1976).
Field bindweed was first noticed in America in Virginia as early as 1739. and by 1900 it
was well established and recognized as a serious weed in most of the western states. In
addition to a progressive spread across America. the weed may have been introduced
several times. For example. it may have been introduced directly into Kansas with
wheat brought from the Ukraine by immigrants about 1875 (Weise & Phillips 1976).
Bindweed is difficult to control because of its extensive root system and prolific seed
production. Roots and rhizomes may cover an area up to 6 m in diameter (Frazier 1943)
and extend down 9 m below the soil surface (Phillips 1978). In addition roots store a
range of sugars. starches. and proteins that can support the plants over long periods
even though top growth may be repeatedly destroyed (Weise & Phillips 1976). Over 11
million seeds may be produced per hectare and they may remain viable in soil for up to 30
years (Timmons 1949).
Seedlings develop deep taproots in a few weeks and in 9 to 11 weeks spread radially by
lateral roots. Within one season a single plant may form a patch of more than 3 m in
diameter (Weise & Phillips 1976).
Control of bindweed but not eradication can be achieved through an integrated programme
of frequent cultivation and selected herbicides. However, with the growing
concern of the overload of chemicals in the environment, their cost. the cost of energy,
and costs in lost production there has been interest in biological control. Mohyuddin
(1969) listed the insects from Calystegia spp. and Convol"lIll1s spp. found by him in
Ontario and by others in other parts of the world. and the University of California and
the USDA jointly mounted a project to survey the Mediterranean area for natural
enemies of Convolvulus (Rosenthal 1980). In all, 140 species of insects. three species of
mites, and three fungi were found attacking C. arvensis and other closely related Convolvulaceae.
Of these, a mite, Eriophyes sp.; a bruchid. Spermophagus sericelts Geoff.; a