Insect-Pest Management and Control (1969) / Chapter Skim
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INSECT SURVEYS
INSECT SURVEYS
Pages 23-33
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From page 23... ...
After the presence of a particular pest has been confirmed, attention may be turned to the second principle of pest detection: No control measures should be undertaken unless it is known that the pest is present in sufficient numbers to cause economic loss. This presupposes that adequate background research has been done with the particular pest and its plant host to establish the "economic threshold": the population level of the pest that will cause sufficient damage to make control economically desirable.
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From page 24... ...
The following broad types may be recognized: qualitative surveys, involving the identification of the different species; quantitative surveys, involving the estimation of the population of one or more species of insect. QUALITATIVE SURVEYS Qualitative surveys may cover the whole fauna of a region, as does the "California Insect Survey," or they may be limited to one or more of the following categories: potential pests, actual pests, and natural enemies.
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From page 25... ...
In many early biologicalcontrol projects, an entomologist made a qualitative survey of the natural enemies of a pest in its supposed country of origin; if any selection of potential control agents for introduction was made, it was based on his intuitive assessment of their roles. As shown below, additional relevant evidence may be obtained by a quantitative assessment of the roles of various parasites and predators.
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From page 26... ...
the future size of the populationprediction and the need for control measures. The special aspects and techniques of these types of quantitative surveys are discussed below, but some consideration must initially be given to the various advantages and disadvantages of the survey method for investigating pest populations.
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From page 27... ...
DAMAGE SURVEYS Damage surveys are often important both in the initial intensive stage of an investigation and in routine control projects. The object of the survey may be to determine the extent to which an insect species causes significant economic damage over a wide area.
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From page 28... ...
Accurate determination of this level is basic to any sequential sampling design, or to any integrated control program. Qualitative and quasi-quantitative estimates of damage obtained rapidly and regularly from a large area, as with the Canadian Forest Insect and Disease Survey, can be useful in indicating long-term changes in a pest's importance, the onset of periodic outbreaks, the success or failure of current control measures, and which pests are of sufficient significance to warrant more-intensive work.
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From page 29... ...
. A high value of r2 will indicate little significant natural control; a low value may indicate very striking changes in numbers after the egg stage, which may be brought about by natural control.
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From page 30... ...
Suspended cone nets may be used to trap aphids (and other insects with low flight speeds) in exposed situations, and sticky traps and sticky nets, because of their greater ability to retain the insects, may be used in a wider range of situations.
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From page 31... ...
When trapping adult insects for survey purposes, it is important to remember that although larger catches may be obtained by using a colored trap or including a bait along with visual attraction, "more" may not be "better." The additional biological errors that are introduced can more than outweigh the statistical advantages of larger catches. Adults of many insects, such as beetles and bugs, may be surveyed by sweeping, beating, and other methods referred to later under Larvae and Pupae.
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From page 32... ...
Surveys of a number of crop insects involve dissecting the stems or stalks of infested plants and counting the number of larvae and pupae present. This procedure, together with counts of the number of plants infested, has been used for many years over wide areas in the United States to determine the annual abundance of the European corn borer, Ostrinia nubilalis (Hubner)
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From page 33... ...
1954. A sequential sampling technique for spruce budworm egg surveys.
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