SPATIAL DISTRIBUTION AND SEQUENTIAL SAMPLING METHODS FOR THE POTATO APHID, MACROSIPHUM EUPHORBIAE (THOMAS) (HOMOPTERA: APHIDIDAE), IN OILSEED FLAX

1995 ◽  
Vol 127 (6) ◽  
pp. 967-976 ◽  
Author(s):  
I.L. Wise ◽  
R.J. Lamb
Keyword(s):  
Sequential Sampling ◽  
Macrosiphum Euphorbiae ◽  
Growth Stages ◽  
Western Canada ◽  
Sequential Decision ◽  
Potato Aphid ◽  
Aphid Density ◽  
Crop Growth Stages ◽  
The Relationship ◽  
Field Plots

AbstractSequential decision plans based on aphid counts and binomial counts of infested plants (presence or absence of aphids) were developed to guide chemical control decisions for die potato aphid, Macrosiphum euphorbiae, on two growth stages of oilseed flax in western Canada. The plans were derived from studies of aphid dispersion among plants in field plots at two locations over 4 years, and verified in samples from 51 commercial fields, in Manitoba. The relationship between variance (s2) and mean aphid density () perplant was loges2 = 0.790 ± 0.050 + (1.649 ± 0.031) loge (n = 69, r2 = 0.98), for both crop growth stages. Neither sweep samples nor pan samples produced reliable estimates of the number of aphids per plant and, therefore, these sampling tools could not replace aphid counts on individual plants. Aphid counts and the binomial method gave similar control decisions with similar amounts of effort, but the aphid counting method required fewer plants to reach a decision. The same decisions were reached in 85–95% of fields by counting aphids on a minimum sample of 25 plants when the crop was in full bloom, or 20 plants at the green boll stage, as with samples of 50–100 plants.

SAMPLING PLANT BUGS, LYGUS SPP. (HETEROPTERA: MIRIDAE), IN CANOLA TO MAKE CONTROL DECISIONS

1998 ◽  
Vol 130 (6) ◽  
pp. 837-851 ◽  
Author(s):  
I.L. Wise ◽  
R.J. Lamb
Keyword(s):  
Sequential Sampling ◽  
Control Plant ◽  
Sequential Decision ◽  
Minimal Sample ◽  
Independent Test ◽  
The Difference ◽  
Edge Sampling ◽  
The Relationship ◽  
Field Plots ◽  
Sweep Net

AbstractPlant bugs in the genus Lygus are pests of canola (Brassica napus L. and Brassica rapa L.) in western Canada and may require insecticidal control. Sweep-net sampling of field plots and commercial fields in southern Manitoba between 1988 and 1995 was used to develop sequential sampling plans for plant bugs in canola to facilitate control. The variance–mean relationships for plant bug catches were defined by Taylor’s power law, and the parameters of the relationships were the same for field plots and commercial fields. Sampling units of 10, 20, 50, and 100 sweeps per sample had variance–mean relationships with the same slope but different intercepts and required different minimal sample sizes. Samples taken at two crop stages had similar variance–mean relationships, but at a later crop stage the intercept of the relationship differed and the parameters were estimated with less precision. Samples taken in two ways along the edges of commercial fields and at various distances into the fields all gave similar estimates of plant bug density, justifying the use of edge sampling. Experienced samplers caught more plant bugs than inexperienced ones, although the difference was primarily due to the number of nymphs rather than adults that were collected, and this difference was less pronounced in the edge samples. Sweep-net sampling collected less than 10% of the plant bugs present in the sampling area. Sequential decision plans are presented for four sampling units and three crop stages. Sampling commercial canola with a sweep net to make decisions on the need to control plant bugs can be completed in as little as 28–35 min. The sampling is most efficiently conducted with a sampling unit of 10 or 20 sweeps taken along the edge of a field. In an independent test of the sampling method, plant bug densities were classified correctly in relation to the need for control in 20 fields using the minimum sample size.

SPATIAL DISPERSION AND SEQUENTIAL SAMPLING OF THE POTATO APHID, MACROSIPHUM EUPHORBIAE (HOMOPTERA: APHIDIDAE), ON PROCESSING-TOMATOES IN OHIO

1984 ◽  
Vol 116 (8) ◽  
pp. 1069-1075 ◽  
Author(s):  
Gregory P. Walker ◽  
Laurence V. Madden ◽  
Donald E. Simonet
Keyword(s):  
Linear Relationship ◽  
Spatial Dispersion ◽  
Sequential Sampling ◽  
Macrosiphum Euphorbiae ◽  
Potato Aphid ◽  
Good Linear ◽  
Mean Crowding ◽  
Linear Fit ◽  
Potato Aphids ◽  
Processing Tomatoes

AbstractSpatial dispersion of potato aphids was studied in fields of processing-tomatoes for 2 years to develop a sequential sampling scheme for the aphid. Potato aphids were found on upper, middle, and lower leaf strata in the percentages 60, 31, and 8. Dispersion was clumped, apterates more so than alates. Among-plant variance was generally greater than within-plant variance. There was a good linear relationship between mean crowding and the population mean and an excellent linear fit between log variance and log mean on all leaf strata for green and pink forms of the aphid and for alates and apterates. The log variance – log mean relationship was used as a basis for sequential sampling.

THE RELATIONSHIP OF EMBRYO COUNTS AND SUCTION TRAP CATCHES TO POPULATIONS DYNAMICS OF MACROSIPHUM EUPHORBIAE (HOMOPTERA: APHIDIDAE) ON TOMATOES IN ONTARIO

1981 ◽  
Vol 113 (12) ◽  
pp. 1113-1122 ◽  
Author(s):  
W. M. Elliott
Keyword(s):  
Adult Life ◽  
Population Trends ◽  
Macrosiphum Euphorbiae ◽  
Large Populations ◽  
Suction Trap ◽  
Relationship Of ◽  
Trap Catches ◽  
The Relationship ◽  
Field Plots ◽  
Populations Dynamics

AbstractThe number of large embryos in adult Macrosiphum euphorbiae (Thomas) was investigated in 1974–77 as a means of forecasting population trends on field tomatoes. In an incubator the embryo count (e) of apterae and alatae was related to the daily birthrate (N) by the equation N = 0.45 e + 0.33, except in the first 4 days of adult life of the apterae. On field plots of tomatoes, e was only satisfactory for forecasting population trends in 1 of 4 years of observations. This probably occurred because the adults were mainly apterae. The relationship between flights of alatae and populations on tomatoes appeared to differ from year to year. In 1974 the number of alatae in large populations in tomato plots was more closely related to the number of alatae trapped in flight with a suction trap in the week after than in the week before the tomatoes were sampled, suggesting many alatae were leaving the tomatoes. In 1975–77, populations on tomatoes were low and the number of alatae on the plots was more closely related to suction trap catches in the week before than in the week after the counts on tomatoes, suggesting many of the alatae on the plots had recently arrived there. The percentage of alatae among adults on field tomatoes declined with days from planting each year. Red forms always constituted ≥ 50% of populations on tomatoes and in flights, the rest being green.

scholarly journals Diminished UV radiation reduces the spread and population density of Macrosiphum euphorbiae (Thomas) [Hemiptera: Aphididae] in lettuce crops

2012 ◽  
Vol 39 (No. 2) ◽  
pp. 74-80 ◽  
Author(s):  
S. Legarrea ◽  
B.M. Diaz ◽  
M. Plaza ◽  
L. Barrios ◽  
I. Morales ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Temporal Dynamics ◽  
Insect Pests ◽  
Cropping Systems ◽  
Macrosiphum Euphorbiae ◽  
Life Table Parameters ◽  
Virus Diseases ◽  
Potato Aphid ◽  
Aphid Density ◽  
Spatio Temporal

UV-absorbing covers reduce the incidence of injurious insect pests and viruses in protected crops. In the present study, the effect of a UV-absorbing net (Bionet) on the spatio-temporal dynamics of the potato aphid on lettuce plants was evaluated. A field experiment was conducted during three seasons in two identical tunnels divided in four plots. A set of lettuce plants were artificially infested with Macrosiphum euphorbiae adults and the population was estimated by counting aphids on every plant over 7 to 9 weeks. Insect population grew exponentially but a significantly lower aphid density was present on plants grown under the UV-absorbing cover compared to a standard 50 mesh net. Similarly, in laboratory conditions, life table parameters were significantly reduced under the Bionet. Moreover, SADIE analysis showed that the spatial distribution of aphids was effectively limited under the UV-absorbing nets. Our results indicate that UV-absorbing nets should be considered as an important component of lettuce indoor cropping systems preventing pesticide applications and reducing the risk of spread of aphid-borne virus diseases.

Crop infestation by aphids is related to flight activity detected with 75 metre high suction traps

2004 ◽  
Vol 57 ◽  
pp. 227-232 ◽  
Author(s):  
D.A.J. Teulon ◽  
M.A.W. Stufkens ◽  
J.D. Fletcher
Keyword(s):  
Positive Relationship ◽  
Rhopalosiphum Padi ◽  
Flight Activity ◽  
Aphid Infestation ◽  
Potato Aphid ◽  
Suction Traps ◽  
Suction Trap ◽  
Trap Catches ◽  
The Relationship ◽  
High Suction

The flight activity of aphid pests of wheat potato lettuce and squash is currently monitored in New Zealand using 75 m suction traps However there has been little research comparing aphid suction trap catches with crop infestation levels The relationship between the average number of aphids (Rhopalosiphum padi) sampled from wheat plants and the average number of aphids caught in weekly 75 m suction trap samples was examined A significant positive relationship indicated that numbers of aphids caught in suction traps reflected the numbers of aphids infesting wheat fields In another experiment potato aphid flights (mostly Myzus persicae) caught in a 75 m suction trap were compared with a nearby windvane trap Aphid numbers in both traps reflected similar trends However the suction trap caught approximately 10 times more aphids than the windvane trap Thus 75 m suction traps provide a useful tool for assessing aphid infestation levels in crops

scholarly journals RNAi efficacy is enhanced by chronic dsRNA feeding in pollen beetle

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jonathan Willow ◽  
Liina Soonvald ◽  
Silva Sulg ◽  
Riina Kaasik ◽  
Ana Isabel Silva ◽  
...  
Keyword(s):  
Rna Interference ◽  
Pest Management ◽  
Oilseed Rape ◽  
Growth Stages ◽  
Short Term ◽  
Pollen Beetle ◽  
Brassicogethes Aeneus ◽  
Crop Growth Stages ◽  
Insecticidal Compounds ◽  
Significant Mortality

AbstractDouble-stranded RNAs (dsRNAs) represent a promising class of biosafe insecticidal compounds. We examined the ability to induce RNA interference (RNAi) in the pollen beetle Brassicogethes aeneus via anther feeding, and compared short-term (3 d) to chronic (17 d) feeding of various concentrations of dsRNA targeting αCOP (dsαCOP). In short-term dsαCOP feeding, only the highest concentration resulted in significant reductions in B. aeneus survival; whereas in chronic dsαCOP feeding, all three concentrations resulted in significant mortality. Chronic dsαCOP feeding also resulted in significantly greater mortality compared to short-term feeding of equivalent dsαCOP concentrations. Our results have implications for the economics and development of dsRNA spray approaches for managing crop pests, in that multiple lower-concentration dsRNA spray treatments across crop growth stages may result in greater pest management efficacy, compared to single treatments using higher dsRNA concentrations. Furthermore, our results highlight the need for research into the development of RNAi cultivars for oilseed rape protection, given the enhanced RNAi efficacy resulting from chronic, compared to short-term, dsRNA feeding in B. aeneus.

Development, Survival, and Fecundity of the Potato Aphid, Macrosiphum euphorbiae (Thomas), at Constant Temperatures

1962 ◽  
Vol 94 (6) ◽  
pp. 667-671 ◽  
Author(s):  
C. A. Barlow
Keyword(s):  
Life History ◽  
Macrosiphum Euphorbiae ◽  
Potato Aphid ◽  
Influence Of Temperature ◽  
Controlled Conditions ◽  
Influence Of Temperature On

Life-history and development of Macrosiphum euphorbiae (Thomas) have been studied by Smith (1919), Patch (1925), and MacGillivray and Anderson (1958). In most of these studies, considerable variation in temperature was experienced. The effects of different constant temperatures have never been reported. The following experiments were conducted to determine the influence of temperature on development, survival, and fecundity of M. euphorbiae under closely controlled conditions.

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