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Cat 8 - Unit 2: Q & A
Terms in this set (46)
What should you do if you are not sure of the identity of a particular pest?
Contact ID Lab at VT for helping identifying insect pests. VCE, FWS, VDGIF
Why is it important to monitor pest populations regularly?
It will help you detect infestations when they are small and easier to control.
What basic information can a pest-monitoring program provide?
1.What species of pests are present.
2. How large the pest population is.
3. How & where the pests are distributed.
4. Whether the pest population is increasing or decreasing.
5. What percentage of the pest population is carring a particular pathogen.
Why are mosquitos a threat to public health?
Because adult females of many species can transmit diseases and parasites while they feed. Many of these diseases can cause serious illness or even death.
What color are mosquito eggs?
When adult females first deposit their eggs, the eggs are white. They darken within 12 - 24 hours.
Where do standing-water vs. floodwater mosquitos typically lay their eggs? How quickly do the eggs hatch?
Standing water mosquitos deposit their eggs directly on the water surface. These eggs may hatch in one to four days depending on temperature. Many floodwater species deposit their eggs on moist soil or other wet surfaces. These eggs may hatch within a few days after being flooded. However, if conditions dry, the fully developed larvae may stay inside the eggs for up to a year waiting for a flood.
What is the purpose of a siphon on most mosquito larvae?
A siphon (air tube) enables the larva to breath when it suspends vertically below the water surface. The siphon is located near the last segment of the larva.
The larvae of which mosquito species breathe through a cluster of abdominal plates instead of a siphon?
Do mosquito pupae move or feed?
They move (and can be very active). They are often called tumblers because of their rapid, tumbling-like movement when disturbed. However, mosquito pupae do not feed.
What are the differences between the diets and mouthparts of male and female mosquitos?
Female mosquitos (and some males) have piercing-sucking mouthparts. They feed mostly on animal blood and plant nectoar. The mouthparts of most male mosquitoes are modified to suck nectar and plant secretions where no piercing is required.
What do most mosquito larvae eat?
Most larvae are filter feeders. These species eat anything that is smaller than about 10 microns. They capture these tiny food particles by vibrating their mouth brushes. This movement sweeps in particles and small organisms from the surrounding water.
What are the two main categories of larval habitats?
Standing water (permanent and transient) and floodwater (including natural and artificial containers as well as floodwater).
What are the two main groups of standing water mosquitoes?
Those that prefer to lay their eggs in permanent water and those that prefer to lay their eggs in transient pools.
Which mosquito genera are often associated with permanent water?
Anopheles, Culex, and Coquillettidia
Give several exampls of permanent water environments where mosquitos often occur.
Freshwater marshes, lakes, ponds and seepage areas, springs, and swamps.
In what areas within a lake or a pond do mosquito larvae typically congregate?
In and around floating or emersed plants.
Which mosquito genera are often associated with transient water?
Culex and Culiseta
Name several examples of transient-water environments where mosquitoes often occur.
Borrow pits and canals, and freshwater drainage ditches.
Under what conditions do borrow pits and canals typically produce larger numbers of mosquitoes?
When they fill in with silt and become overgrown with plants.
How do standing water and floodwater mosquitos typically overwinter or survive harsh conditions?
Most standing water mosquitos overwinter as mated, engorged females; floodwater mosquitos overwinter in the egg stage.
What are the two main groups of floodwater mosquitoes?
Those that prefer to lay their eggs in large, flooded areas and those that prefer to lay their eggs in artificial containers and tree holes.
Which mosquito genera are often associated with large flooded areas?
Ochlerotatus, Aedes, and Psorophora
Give three examples of floodwater environments where mosquitos often occur.
Saltmarshes, rain pools, and floodwater pools.
What is a salt marsh?
A salt marsh is a wt area that is part of the coastal plain. Salt marshes contain maily saltwater and are not usually fed by rivers. Most salt marshes have a well defined drainage network. Salt-tolerant herbaceous plants and typical salt grasses dominate this type of habitat. A single plant species often covers a large areas of salt marsh.
What are salt or brackish water ditches?
Salt or brackish water ditches are filled with salt or brackish water and contain flora and fauna common to these ecosystems. They may occur when ditches near salt amrshes are filled by the marshes due to tidal action or storms.
Which mosquito genera are often associated with the water that collects in artificial containers and tree holes?
Ochlerotatus, Aedes, Culex, Toxorhynchites, and Orthopodomyia
Give several examples of artificial containers that collect water in which mosquitos could breed.
Cans, fish pools, cisterns, rain barrels, gutters, old tires, and similar objects.
What is the purpose of a mosquito surveillance program?
These programs tell you how effective your control actions are over time. Although they do not tell you the exact size of a mosquito population, they can show changes in mosquito numbers. They also indicate how diverse populations are over time in the various habitats that you monitor.
What should a basic mosquito surveillance program monitor?
1. The density of adult and larval populations.
2. The species composition.
3. Rainfall and tide information.
4. Where each species is breeding.
Depending on your situation, you may also want the surveillance program to:
1. Keep track of the prescence of arboviral diseases in birds and mosquitoes.
2. Detect and monitor container breeding species.
3. Sample floodwater mosquito eggs to locate breeding sites.
What information should your record on a map when conducting mosquito surveillance programs?
You should outline the treatment areas and the possible flight range of mosquitoes from breeding sites. On your map, you should also show how far your control efforts might penetrate into populated areas. Use symbols and numbers to mark larval and adult sampling stations.
When conducting surveys, why is it so important to survey the same place in the same way?
To avoid comparing unlike types of data.
What tools can help make sure you record uniform and complete data?
Data recording forms and devices.
What is the purpose of mosquito egg surveys?
To determine exactly where mosquitoes are breeding.
What techniques should you use to monitor the eggs of floodwater mosquitoes vs. container breeding mosquitoes?
Sod sampling and egg separatioin work best for floodwater species. Ovipostion traps are best for monitoring container breeding mosquitoes.
Describe how to sample sod for mosquito eggs.
Sod sampling involves removing small clumps of soil from target areas and testing them to see which, if any, mosquito species are present. To take a sod sample, first, remove a piece of sod that is about 1 inch thick. It should consist of 8 cubic inches of soil and vegetation. Store it for a week or more to allow the mosquito embryos time to develop within the eggs. Then, place the sample in a glass jar and flood it with water. When the larvae hatch, you can identify them. You might need several back to back floodings and dryings to get enough eggs to hatch.
How do egg separtion machines work?
These machines separate mosquito eggs from soil and debris by: mechanical, washing, screening, floating eggs in a saturated salt solution while the debris sinks
Describe how to make an oviposition trap for mosquitoes.
You can make oviposition traps out of food cans (large coffee cans) or pint jars painted black inside and outside. Place the traps in shaded areas at a height no greater than 3 3/4 feet. Fill them with water and place a few dried leaves at the bottom of each container. Then, create an oviposition substrate from materials such as seed germination paper, muslin, Formica, balsa wood, or wooden tongue depressor. Place the substrate vertically inside the container with the water covering about half of it. Gravid females will used the substrate to lay eggs just above the water level.
Describe the best way to collect mosquito larvae with a dipper.
You will need to adjust your sampling technique for each species you target.l For example, the best way to collect anopheline larvae is to use a skimming movement with a dipper, pressing one side just below the surface. Be sure to finish the stroke just before the dipper is full. If you fill the dipper to the point that it runs over, you will lose larvae. Where clumps of erect vegetation are present , it is vest to press the dipper into a clump with one edge depressed so that the water flows from the plant into the dipper. Culicine larvae such as Ae. vexans, Oc. sollicitans, or Psorophora spp., on the other hand, are more likely to dive below the surface when disturbed. For this reason it is best to used a quicker chopping motion of the dipper when you sample for these groups.
When using a dipper to sample shoreline areas for mosquitoes, why should you approach the sampling site slowly and quietly?
Water movement and/or shadows may cause mosquito larvae to dive to the bottom.
How should you collect larvae of mosquitoes that breed in tree holes and artifical containers?
Because these containers are often too small for an ordinary dipper, you should transfer the water with a turkey baster or siphon it into a dippper or pan wheret he larvae are visible.
What time of day should you perform landing and biting collections of mosquitoes? Why?
Near sundown becaused many mosquitoes are most active at this time.
Why is it important that the same person perform landing and biting counts for a given mosquito surveillance program?
Because some people are more attractive to mosquitoes than others.
When surveying adult mosquitoes, when might you want to collect them alive?
To breed the mosquitoes for disease transmission studies or to determine their susceptibility to pesticides. Any arbobiral testing must also be done on fresh specimens
What types of mosquitoes can you capture using an insect sweep net?
Mosquitoes that rest in grass and other vegetation during the day (ex. Ae. vexans and Oc. sollicitans).
What items can you use to attract adult mosquitoes to bait trap?
Animals (young chickens, pheasants, house sparrows, or other birds), dry ice, or a combination of these.
Where will a light trap collect the most adult mosquitoes?
Light traps work best when they are 30 or more feet from building in open areas near trees and shrubs. Be sure the trap is far from other lights, areas open strong winds, and industrial plants give off smoke or gas. In addition, the light in the trap should be 5 1/2 to 6 feet above the ground when your mount it on a post or hang it from a tree.
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