142
0 . R. POTTS AND a. P. VICKERMAN
I
TAESLE VIII
The densities of wheat bloseom midges (mainly Sitodiplosis mosellana) in herbicide
treated cereal c r o p , West Swrcrex, mid June 1970 and 1971
Current
Crop in
*Adults per m2 in mid June
crop
previous year
1970
197 1
31.52 f 27.97
Wheat
993
Wheat
(2)
(11)
Other
182.50 It 30.81
7.56f 7.05
(28)
(19)
Wheat
109.47 f 16.31
1
Spring barley
(7)
(3)
Other
38-1Of 3.82
5.08f 1.30
(73)
(62)
~~~
~
~~~~
* The sample size is given in parentheses beneath the mean. Most samples contained
mme Contarinia tritici.
survey in the south-east region of England (Duthoit, 1968) the mean
percentage tiller attack varied from 54% in 1965 to zero in 1967. The
relationship between cereal leaf miner damage and yield is not known
although it is thought losses are not appreciable.
Attacks by the saddle gall midge Haplodiplosis equestris (Wagn.) have
increased in recent years in parts of England (Gair, 1967). In the
1950’s there were numerous reports of attacks on cereal crops in Europe
(Johansson, 1961; Hulshoff, 1963) and the build-up of this pest has been
attributed to continuous cereal growing. On the Continent and in
Denmark it has risen in numbers to the level which makes routine
spraying an economic operation. The results of a three-year survey of
saddle gall midge on spring barley crops in the eastern counties of
England (Woodville, 1970) suggested that there was a positive correlation between the amount of galling and the number of previous wheat
crops. It has been shown (Thygesen, 1965) that heavy soils are more
suitable for midge build up than light ones and Woodville (loc. cit.)
suggested that saddle gall midge infestation was correlated with the
soil type. The economic status of saddle gall midge has not yet been
adequately evaluated.
2. Percentage composition and trophic structure
In 1970 and 1971 the percentage composition of the adult dipterous
fauna of the cereal fields in the study area was measured and the
results are given in Table IX. The results were based on samples taken
0 . R. POTTS AND a. P. VICKERMAN
I
TAESLE VIII
The densities of wheat bloseom midges (mainly Sitodiplosis mosellana) in herbicide
treated cereal c r o p , West Swrcrex, mid June 1970 and 1971
Current
Crop in
*Adults per m2 in mid June
crop
previous year
1970
197 1
31.52 f 27.97
Wheat
993
Wheat
(2)
(11)
Other
182.50 It 30.81
7.56f 7.05
(28)
(19)
Wheat
109.47 f 16.31
1
Spring barley
(7)
(3)
Other
38-1Of 3.82
5.08f 1.30
(73)
(62)
~~~
~
~~~~
* The sample size is given in parentheses beneath the mean. Most samples contained
mme Contarinia tritici.
survey in the south-east region of England (Duthoit, 1968) the mean
percentage tiller attack varied from 54% in 1965 to zero in 1967. The
relationship between cereal leaf miner damage and yield is not known
although it is thought losses are not appreciable.
Attacks by the saddle gall midge Haplodiplosis equestris (Wagn.) have
increased in recent years in parts of England (Gair, 1967). In the
1950’s there were numerous reports of attacks on cereal crops in Europe
(Johansson, 1961; Hulshoff, 1963) and the build-up of this pest has been
attributed to continuous cereal growing. On the Continent and in
Denmark it has risen in numbers to the level which makes routine
spraying an economic operation. The results of a three-year survey of
saddle gall midge on spring barley crops in the eastern counties of
England (Woodville, 1970) suggested that there was a positive correlation between the amount of galling and the number of previous wheat
crops. It has been shown (Thygesen, 1965) that heavy soils are more
suitable for midge build up than light ones and Woodville (loc. cit.)
suggested that saddle gall midge infestation was correlated with the
soil type. The economic status of saddle gall midge has not yet been
adequately evaluated.
2. Percentage composition and trophic structure
In 1970 and 1971 the percentage composition of the adult dipterous
fauna of the cereal fields in the study area was measured and the
results are given in Table IX. The results were based on samples taken