III.) Sampling & Detection, Tools & Techniques Flashcards
Sampling and Detection
Tools and Techniques
A.) Visual Inspection B.) Knockdown/Suction C.) Netting D.) Trapping E.) Damage estimates F.) Pest clues G.) Laboratory Tests/Diagnostic Aids
A.) Visual sampling
Involves examining a specific number of plants, plant parts, or infested areas, for pest or their damage.
The most common of sampling techniques; sometimes requiring a hand lens or magnifying device.
This can include presence-absence sampling, counting each individual per sampling unit (leaf, root gall, hour of inspection, etc.)
Weed surveys commonly involve walking through a field in random patterns and reading the degree of infestation for each weed species on a weed survey form using visual inspection.
B.) Knockdown techniques
Average pest density=The number of pest individuals in all samples ÷total samples inspected.
Relative pest density= The number of samples with species present ÷ total samples inspected
Relies on physically removing pests and beneficial’s (if present) from a portion of a plant onto a tray, cloth, lid, sweep nets or other collection device; then counting them.
The collection device is held beneath a branch, plant, or general area being beaten.
Using the knockdown technique one can calculate the average pest density and if necessary the relative pest density.
Vacuum devices can be used as well.
C.) Trapping techniques
These are used to sample mobile insects, through the application of some sort of bait or attractant.
a. ) bait/food traps
b. ) pheromone traps
c. ) light traps
d. ) sticky traps
e. ) pitfall traps
Ca.) Bait traps
Provoke a response by using the pests food source as a stimulus. For example bait traps are used to monitor dried fruit beetles in figs.
Using culled fruit, water, and yeast attracts the beetles before the fruit has began to ripen. When the count begins to drop off in the trap, it means that the beetles are being attracted to the fruit and therefore should be controlled.
Cb.) Pheromone traps
Use chemicals that allow insects to communicate with one another. Most mimic the reproductive pheromones that pests release to attract individuals for mating. These chemicals are added to various types of dispensers and lures.
These traps are quite effective because they are economical and specific to a target pest.
They allow managers to determine when reproducing adults are in the field thus aidi
Cc.) Light traps
Another type of trap that attracts and captures arthropod pests including many night flying species.
It’s typical light trap consists of an ultraviolet fluorescent light above a collection jar that contains a neutralizing agent.
Primarily used for monitoring the emergence were migration dates of certain pests including mosquitoes, months, and some beetles.
When does it vantage of light traps is that they attract so many other pest species and can be very time-consuming to separate.
Cd.)Sticky traps
Adult white flies, thrips, aphids, and other pests and beneficial insects parasites are monitored with sticky traps.
The owners are randomly catch insects or attract them through the use of color.
A general recommendation for most greenhouse insect pests is to use one trap per every 10,000 ft.² of growing area.
Inspect the cards every week and record the results in order to create a management plan.
Ce.) Pitfall traps
Randomly capture orthopod species such as ground beetles, spiders, and springtails found on the soil surface.
These traps consist of a glass or plastic container sunk into the ground with the mouth even with the soil surface; they capture any arthropod that lands inside, with a preservative to immobilize the pest.
E.) Damage estimates
In many situations, the first indication of a pest problem is the visible damage on the host; looking for damaged symptoms is often a good technique for pests that are hard to detect.
Sometimes detection can be used along side severity indexes which are similar to visual injury scales.
Levels of pest damage in previous years are often used in the decision-making for treatments the following spring.
Damage estimates must be evaluated with caution sense other factors such as soil type and climate can also influence the results.
Damage sampling is only an indicator of pest activity and should be combined with other sampling methods for accurate decision.
F.) Pest Population Clues
Besides damage, pest populations often leave other visible clues indicating their presence for example: fecal pellets, tracking,mounds, and burrows.
Honeydew droplets can be collected from sucking insects such as aphids in the springtime using water sensitive cards placed underneath branches to make educated guesses about the pest population density.
G.) Laboratory Tests
a. ) Microscopes for Arthropod Identification
b. ) Nematode Soil Samples
c. ) Soil Tests for Weeds
d. ) Plant Disease Diagnosis
Ga.) Microscopes for identification
Pests and beneficial sometimes must be viewed under a microscope for positive ID.
One example is the that of spider mites.
In situations where parasites are important one can determine the percentage of parasites can be confirmed by collecting the pest and observing underneath a microscope to test for presence of the beneficial.
Gb.) Nematodes soil samples
Soil samples are regularly taken for nematodes and submitted to a qualified laboratory for extraction and if necessary identification of the nematode species present.
Gc.) Soil tests for weeds
Soil samples can also be collected and evaluated for the presence of weed seeds not yet germinated and present before the cropping season.
This test is especially valuable when prior information on the field is not available and a weed survey cannot be performed.
Germination of the seeds present in the soil sample is a useful test for evaluating the effectiveness of an herbicide application.
Collect soil samples from the top 2 to 3 inches of soil from at least 10 to 20 random locations in the field.
