RELATIONSHIP BETWEEN INFESTATION LEVELS AND YIELD LOSS CAUSED BY WHEAT MIDGE, SITODIPLOSIS MOSELLANA (GÉHIN) (DIPTERA: CECIDOMYIIDAE), IN SPRING WHEAT IN SASKATCHEWAN

1985 ◽  
Vol 117 (5) ◽  
pp. 593-598 ◽  
Author(s):  
O.O. Olfert ◽  
M.K. Mukerji ◽  
J.F. Doane

AbstractLosses in yield of spring wheat due to infestations of Sitodiplosis mosellana (Géhin) were determined for 700 000 ha of arable land in northeast Saskatchewan, Canada in 1983. The proportion of kernels infested (y) was a power function of the number of wheat-midge larvae (x) (y = 35.3x0.725). One, 2, 3, and 4 larvae per kernel resulted in a level of infestation of 38, 58, 78, and 96%, respectively. There was no significant difference between infestation levels from fields sampled at the heading stage of crop growth and the estimates of infestation levels for these fields at harvest time. Yield of grain (y) was negatively exponential to an increase in level of infestation (x) (ln y = 5.7−0.017x). Infestations of 30, 60, and 90% reduced yields of spring wheat by 40, 65, and 79%, respectively. The average decrease in crop yield in the study area was about 30%, which resulted in estimated losses in total gross revenue of about $30 million.

1999 ◽  
Vol 131 (3) ◽  
pp. 387-397 ◽  
Author(s):  
R.J. Lamb ◽  
I.L. Wise ◽  
O.O. Olfert ◽  
J. Gavloski ◽  
P.S. Barker

AbstractThe wheat midge Sitodiplosis mosellana (Géhin) occurred in all wheat-growing areas of Manitoba during 1993–1997, with 95% of spring wheat fields having some seeds infested by larvae. The level of infestation varied, but each year in excess of 20% of seeds were infested in some fields. Infestation levels in adjacent fields were more similar than in fields separated by a few kilometres. Within fields, the infestation was similar at the edge and near the centre. Wheat midge larvae also overwintered in, and adults emerged from, fields in all wheat-growing areas of Manitoba. Adults emerged from the end of June to the end of July most years, and the peak period for adult flight was mid-July, about 1 month later than in parts of Europe where winter wheat predominates. The timing of the emergence was similar from place to place and year to year. Females constituted 95% of insects caught in a flight trap. The first 10% and 50% of the flight occurred on 9 and 16 July, respectively, and the timing of the flight was not related to growing degree-days. In early August, mature larvae began dropping from wheat heads. The timing of infestation of spring wheat was variable among years because of differences in timing between midge flights and the susceptible heading stage of the crop. Nevertheless, the wheat midge flight usually coincided with the susceptible stage of the spring wheat crop.


2014 ◽  
Vol 146 (3) ◽  
pp. 335-346 ◽  
Author(s):  
M.A.H. Smith ◽  
I.L. Wise ◽  
S.L. Fox ◽  
C.L. Vera ◽  
R.M. DePauw ◽  
...  

AbstractSpring wheat varieties with the Sm1 gene for resistance to wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were compared with susceptible wheat (Triticum Linnaeus; Poaceae) with respect to sources of yield loss and reduction in market value from wheat midge feeding damage. Four resistant varietal blends (90% Sm1 wheat plus 10% susceptible refuge) and four susceptible cultivars were grown in replicated experiments at eight locations in western Canada. Frequencies and 1000-kernel weights of undamaged and midge-damaged seeds were assessed before harvest by dissecting samples of ripe spikes, and after harvest in samples of cleaned grain. Spike data were used to estimate yield losses from reduced weight of damaged seeds and loss of severely damaged seeds (⩽8 mg) at harvest. Among midge-damaged seeds in spikes, few were severely damaged in resistant varietal blends, whereas most were severely damaged in susceptible cultivars. Cleaned, harvested grain of resistant varietal blends and susceptible cultivars had similar frequencies of midge damage and were assessed similar market grades. The primary benefit of midge-resistant wheat was reduced yield loss due to seed damage by wheat midge larvae. Resistant wheat did not protect against loss of market grade, but market value could increase due to larger yields.


Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Roberte M. D. Makowski

The competitive ability of annual round-leaved mallow was determined in spring wheat and lentil at Indian Head and Regina, Saskatchewan, in 1985 and 1986 using paired quadrats. Significant biomass and seed yield loss occurred in three of four tests in lentil and two of three tests in spring wheat. Differences in numbers of wheat tillers produced between weedy and weed-free plots were found in three of four tests. A two-variable model comprised of early season crop density loss and round-leaved mallow biomass best accounted for the majority of variation in crop yield loss for both lentil and wheat, and tiller density loss in wheat. In 1985 at Indian Head, where no yield loss occurred for either wheat or lentil, round-leaved mallow had been seeded immediately before the crop. Greater yield losses occurred at Regina, in the presence of an older, well-established infestation. In the years and locations with the greatest crop yield losses, round-leaved mallow emerged before the crop causing poor crop emergence. At Regina in 1986, crop yield losses were more than 60% in wheat and 90 to 100% in lentil because of large differences in crop density between weed-free and weedy subplots. Round-leaved mallow exhibited great variability in growth, producing more biomass per plant, more capsules per plant, and more capsules per gram of biomass in the less competitive crop, lentil, than in wheat. Density and biomass of round-leaved mallow were not correlated; with a density of 200 plants m−2, round-leaved mallow biomass in wheat ranged from 100 to 500 g m−2; while in lentil, from 200 to as high as 1000 g m−2, approximately double the range found in wheat. The type of round-leaved mallow infestation (newly seeded or well-established) and environmental conditions (mainly early season precipitation) account for differences between sites and between years.


1996 ◽  
Vol 128 (3) ◽  
pp. 367-375 ◽  
Author(s):  
R.H. Elliott ◽  
L.W. Mann

AbstractIn a 3-year field study, potted plants of ‘Katepwa’ wheat, Triticum aestivum L., were exposed to ovipositing wheat midge. Sitodiplosis mosellana (Géhin), to determine when spikes are most susceptible to damage. After exposure, plants were maintained under controlled conditions for 4 weeks and examined for wheal midge larvae and damaged kernels, ‘Katepwa’ wheat became susceptible to wheat midge damage shortly after spikes emerged from the boot leaf. Location of larvae and damaged kernels within spikes was influenced by the duration spikelets were exposed to oviposition and pattern of anthesis within spikes. In 1992, frequencies of larvae and damaged kernels were 60–90 times higher in spikes exposed to oviposition during advanced heading (stages 57–59, Zadoks’ code) than in those exposed during flowering (stages 61–69). Kernel damage in spikes exposed to oviposition during stages 57–59, 61–65, and 65–70 was 48.5, 3.2, and 0.2%, respectively, in 1993 and 21.2, 1.0, and 0.6%, respectively, in 1994. Data indicated that susceptibility to midge damage declined 15- to 25-fold between heading and early anthesis and 35- to 240-fold between heading and advanced anthesis. Potential factors contributing to these declines and concomitant reductions in larval frequencies are discussed.Commercial fields of ‘Katepwa’ wheat should be monitored for ovipositing wheat midge throughout heading (stages 51–59) when spikes are most vulnerable to damage. Larval survival and kernel damage were so low after stage 61 that monitoring during anthesis should be unnecessary. Intensive inspection of fields throughout heading would ensure that chemical treatments are applied when they are necessary and most effective.


2000 ◽  
Vol 132 (5) ◽  
pp. 591-605 ◽  
Author(s):  
R.J. Lamb ◽  
R.I.H. McKenzie ◽  
I.L. Wise ◽  
P.S. Barker ◽  
M.A.H. Smith ◽  
...  

AbstractCultivars of winter wheat, Triticum aestivum L., previously identified as possible sources of resistance to wheat midge, Sitodiplosis mosellana (Géhin), were crossed with spring wheat to produce lines with a spring growth habit and assure synchrony between insect and plant. Many of the lines showed low levels of infestation by wheat midge in the field, and 21 of these were tested for resistance in the laboratory. All test lines exhibited resistance, ranging from 58 to 100% suppression of larvae and 70 to 100% suppression of seed damage, compared with a susceptible line. Larval development was delayed and survival was reduced on all lines. This antibiosis was associated with a hypersensitive reaction in the seed surface. The hypersensitive reaction, or feeding damage by young larvae before they died, reduced the biomass of some infested resistant seeds by 28% compared with over 60% for infested susceptible seeds. Some lines also reduced the level of infestation either through oviposition deterrence or a resistance which prevented newly hatched larvae from establishing on the seed surface. A few lines also reduced the hatching rate of wheat midge eggs. The resistance was equally effective in field trials during two consecutive summers in Manitoba and Saskatchewan, with at least a 20-times difference in the level of infestation between susceptible and resistant wheats. No larvae could develop to maturity on some resistant lines. Large plots of one resistant line produced less than 1% as many larvae as a typical susceptible wheat, and the larvae that did survive produced few, small adults. This resistance is the first documented case of a high level of true resistance to wheat midge in spring wheat, distinct from asynchrony between the insect and susceptible stage of the plant. The antibiosis component of the resistance is currently being incorporated in cultivars suitable for production in western Canada.


2010 ◽  
Vol 142 (6) ◽  
pp. 574-583 ◽  
Author(s):  
A.H. Gharalari ◽  
M.A.H. Smith ◽  
S.L. Fox ◽  
R.J. Lamb

AbstractWheat, Triticum L. (Poaceae), varieties with deterrence to oviposition by the wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), can be useful in reducing seed damage. The behaviour of ovipositing females on spring wheat, T. aestivum L., with and without oviposition deterrence was investigated to account for observed differences in oviposition on deterrent and nondeterrent hosts. On deterrent wheat, 34% of females landing oviposited compared with 100% of females landing on nondeterrent wheat. The sequence of female behaviours just prior to egg-laying on deterrent spikes was similar to that on nondeterrent spikes. The length of time required to lay an egg and mean egg-batch size were similar on deterrent and nondeterrent wheat, but females spent nearly twice as long on the latter. After landing on deterrent wheat, females took longer to begin ovipositing and longer to leave after the last oviposition event than did females on nondeterrent wheat, which further reduced the time available for oviposition on deterrent compared with nondeterrent wheat. As a result of these behavioural differences, deterrence reduced oviposition by more than 60%.


2018 ◽  
Vol 150 (5) ◽  
pp. 675-683 ◽  
Author(s):  
Erik R. Echegaray ◽  
Christopher R. Barbour ◽  
Luther Talbert ◽  
Robert N. Stougaard

AbstractThe wheat midge, Sitodiplosis mosellana Géhin (Diptera: Cecidomyiidae), is a serious pest of spring wheat in North America. Currently, most commercial cultivars in the state of Montana, United States of America are susceptible. A study was conducted to assess the variability of adapted spring wheat cultivars to wheat midge infestations. A secondary objective was to determine the relationship between wheat midge infestation levels and spring wheat agronomic traits, including yield, test weight, grain protein, plant height, and heading date. This relationship was determined by evaluating 16 hard red spring wheat cultivars over a six-year period at the Northwestern Agricultural Research Center, near Kalispell, Montana. Levels of infestation had a negative impact on grain yield and test weight. Overall, the average infestation level was 40 larvae/spike with the lowest being observed with “Reeder” and the highest for “Thatcher”. Concurrently, “Reeder” had the highest yield, whereas “Thatcher” had the lowest yield and the highest grain protein, demonstrating that wheat midge infestations were positively associated with grain protein. Heading date had a positive association with midge density with higher infestations associated with later maturing cultivars. The economic injury level was estimated at 12 and 20 midge larvae/spike for a market price of USD $0.27 and USD $0.16/kg, respectively.


2007 ◽  
Vol 139 (1) ◽  
pp. 133-140 ◽  
Author(s):  
M.A.H. Smith ◽  
I.L. Wise ◽  
R.J. Lamb

AbstractSmall numbers of larval wheat midge, Sitodiplosis mosellana Géhin, survived and matured in each of five field seasons in a plot of spring wheat carrying the Sm1 gene for antibiosis resistance against this insect. Wheat midge developing on resistant wheat had higher survival in the laboratory than in the field, but survival was always very low compared with that of larvae developing on susceptible wheat. The mass of these larvae and their survival during diapause were approximately half those of larvae developing on susceptible wheat in both the laboratory and the field. The survival of some wheat midge larvae on resistant wheat, and their reduced mass, is consistent with the hypothesis that a virulence allele allowing adaptation to Sm1 is present in the population. Assuming this to be the case, the frequency of the allele in the population was estimated to be between 0.8 × 10−4 and 1.6 × 10−2, if surviving larvae are heterozygous for the allele. Although rare, a virulence allele occurring at this frequency would likely allow the wheat midge to overcome the resistance gene Sm1 once resistant wheat is grown over a wide area.


2005 ◽  
Vol 78 (1) ◽  
pp. 17-22 ◽  
Author(s):  
D. Mongrain ◽  
L. Couture ◽  
J.-P. Dubuc ◽  
A. Comeau

Samples of wheat spikes (Triticum aestivum) were collected in the summer of 1995 from different crop districts in Quebec and the occurrence of orange wheat blossom midge (Sitodiplosis mosellana) and seed microflora were determined. Estimated yield loss caused by wheat midge larvae averaged 6.3%. The percentage of infested spikes was significantly correlated with total seed contamination by fungi and bacteria (r = 0.79). The specific occurrence of Fusarium graminearum in grains was also significantly correlated with number of larvae per spike (r = 0.67) or per spikelet (r = 0.67). Consequently, the wheat midge might play a role in dissemination of F. graminearum.


2004 ◽  
Vol 18 (3) ◽  
pp. 509-520 ◽  
Author(s):  
Johnathon D. Holman ◽  
Alvin J. Bussan ◽  
Bruce D. Maxwell ◽  
Perry R. Miller ◽  
James A. Mickelson

Integrated weed management practices, such as crop rotation and increased seeding rates, potentially improve weed management. Yet, few studies compare competitive interactions of weeds with different crops. This research quantified the impact of Persian darnel on spring wheat, canola, and sunflower yield across different seeding rates. Increasing crop density increased yield when Persian darnel affected crop yield early in physiological development. Crop yield loss was estimated to reach 83, 70, and 57% for spring wheat, canola, and sunflower, respectively, at high Persian darnel densities. Persian darnel reduced spring wheat yield by limiting the number of tillers per plant and seed per tiller; reduced canola yield by limiting the number of branches per plant, pods per branch, and seed per pod; and reduced sunflower yield by limiting the number of seed per plant. Persian darnel affected crop growth early in physiological development, indicating that interspecific interference occurred early in the growing season. Cultural and resource management aimed at reducing Persian darnel impact on resource availability and crop yield components will reduce Persian darnel impact on crop yield.


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