140
a. R. POTTS AND U. P. VICKERMAN
jackets (Tipula spp.) and the wheat blossom midges (Contarinia
tritici (Kirby) and Sitodiplosis mosellana GBhin).
Oscinella frit was first reported as an agricultural pest in this country
in 1888 (Ormerod, 1889) and since that time a considerable amount of
information has been published on the association of this species with
cereal crops (Cunliffe, 1921, 1924; Cunlif€e et al., 1925; Southwood and
Jepson, 1962). In Britain it is best known as a pest of late-sown spring
oats in which the larvae feed during the tiller and panicle stages.
Winter-sown crops of wheat and oats may also be attacked as a result
either of direct oviposition on the crop or of the migration of the larvae
from grassland which has been ploughed in. Spring wheat may occasionally be attacked, but attacks on barley are rare. More recently crops
of grain maize have been extensively damaged by this pest in southern
England.
Besides 0. frit the genus Oscinella contains a number of species with
very similar structure and biology. With the exception of 0. pusilla
Meigen, which is probably rare in this country, the other species do
not oviposit on cereals (Vickerman, in prep.). Although some Oscinella
larvae are able to migrate from buried grass into winter-sown crops
(Heard and Hopper, 1963) and cause damage, the larvae, with the
exception of those of 0. frit. and 0. nigerrima Macq., are unable to
complete their development (Vickerman, in prep.). I n 1970 and 1971 a
number of winter wheat crops in the study area were severely damaged
by larvae of 0. fTit which had migrated from ploughed-in ley grasses.
Other genera reported to be pests of cereals (e.g. Cetema, Opomyza,
Geomyza and Chlorops) have not been extensively studied and owing
to the lack of knowledge regarding the morphology of the adults and
developmental stages, many of the statements made about the biology
of many of these Acalypterate Diptera (including the genus Oscinella)
must be suspect.
Wheat bulb fly, Leptohylemyia coarctata, is known as a pest of
winter-sown crops of wheat, rye and barley; unlike most pests, it does
not lay eggs on or near the host plant but in bare soil. Widespread and
severe attacks in the eastern counties of England in the early 1950’s
prompted a series of investigations into the biology and behaviour of
this pest (Raw, 1954, 1955; Long, 1958). Although infestations declined
in the latter part of that decade (Raw, 1967), in the 1960’s damaging
infestations occurred again, and during the period 1962-1964 about
117 000 ha of the 850 000 ha of wheat were sown with insecticidedressed seed as a precaution against attacks by wheat bulb fly (Anon,
1969). Recent investigations on the wheat bulb fly (Bardner, 1968;
Legowski et al., 1968; Bardner et al., 1970) reflect the continuing
importance of this pest today.
a. R. POTTS AND U. P. VICKERMAN
jackets (Tipula spp.) and the wheat blossom midges (Contarinia
tritici (Kirby) and Sitodiplosis mosellana GBhin).
Oscinella frit was first reported as an agricultural pest in this country
in 1888 (Ormerod, 1889) and since that time a considerable amount of
information has been published on the association of this species with
cereal crops (Cunliffe, 1921, 1924; Cunlif€e et al., 1925; Southwood and
Jepson, 1962). In Britain it is best known as a pest of late-sown spring
oats in which the larvae feed during the tiller and panicle stages.
Winter-sown crops of wheat and oats may also be attacked as a result
either of direct oviposition on the crop or of the migration of the larvae
from grassland which has been ploughed in. Spring wheat may occasionally be attacked, but attacks on barley are rare. More recently crops
of grain maize have been extensively damaged by this pest in southern
England.
Besides 0. frit the genus Oscinella contains a number of species with
very similar structure and biology. With the exception of 0. pusilla
Meigen, which is probably rare in this country, the other species do
not oviposit on cereals (Vickerman, in prep.). Although some Oscinella
larvae are able to migrate from buried grass into winter-sown crops
(Heard and Hopper, 1963) and cause damage, the larvae, with the
exception of those of 0. frit. and 0. nigerrima Macq., are unable to
complete their development (Vickerman, in prep.). I n 1970 and 1971 a
number of winter wheat crops in the study area were severely damaged
by larvae of 0. fTit which had migrated from ploughed-in ley grasses.
Other genera reported to be pests of cereals (e.g. Cetema, Opomyza,
Geomyza and Chlorops) have not been extensively studied and owing
to the lack of knowledge regarding the morphology of the adults and
developmental stages, many of the statements made about the biology
of many of these Acalypterate Diptera (including the genus Oscinella)
must be suspect.
Wheat bulb fly, Leptohylemyia coarctata, is known as a pest of
winter-sown crops of wheat, rye and barley; unlike most pests, it does
not lay eggs on or near the host plant but in bare soil. Widespread and
severe attacks in the eastern counties of England in the early 1950’s
prompted a series of investigations into the biology and behaviour of
this pest (Raw, 1954, 1955; Long, 1958). Although infestations declined
in the latter part of that decade (Raw, 1967), in the 1960’s damaging
infestations occurred again, and during the period 1962-1964 about
117 000 ha of the 850 000 ha of wheat were sown with insecticidedressed seed as a precaution against attacks by wheat bulb fly (Anon,
1969). Recent investigations on the wheat bulb fly (Bardner, 1968;
Legowski et al., 1968; Bardner et al., 1970) reflect the continuing
importance of this pest today.