Evaluating Establishment and Impact of Galerucella in the Field
Once Galerucella beetles have been released into a purple loosestrife infested wetland, steps need to be taken to follow their progress and impacts. It is the responsibility of each cooperator to determine the success or failure of their release. In order to do this, a standardized set of information will be collected from each release site.

Establishing Sample Quadrats
On the day of the release it is important to establish standardized units of area from which data will be collected. These are referred to as sample quadrats. Five or more quadrats will be established in each wetland where beetles have been released. This will allow for the statistical comparison of data collected from the same unit of area during each sample outing. Purple loosestrife density, plant characteristics and Galerucella abundance will be recorded from these permanent quadrats. Data will be collected in the spring after beetle emergence, and again in the fall after beetle activity has ceased.

Three quadrats should be randomly distributed within a 10 m (meter) by 10 m zone encompassing the initial point of beetle release. Place a post in each corner and in the center of the 10 m by 10 m zone. A minimum of two additional quadrats should be placed ten meters from the center of the release site in two different directions. Additional pairs of quadrats may be placed at 50, 100 meters, etc.

Purple loosestrife plants must be included within each quadrat
Place quadrats where they will not be disturbed by hikers, hunters, vandals, etc. Give each quadrat a number and use that number to identify it each time data is collected.

Each quadrat is one meter square and identified with marker poles in at least two of the corners. Use markers that will last for several years, we recommend 3/4" PVC pipe sunk two to three feet into the wetland with at least three feet showing above ground. A measuring tape or meter stick may be used to measure the boundaries of the quadrat. We use 3/4" PVC connected with 90 degree elbows at the corners to form a square which is one meter on a side. Marker poles in each of two opposing diagonal corners of the quadrat allow the PVC square to be placed in the same spot each time.

All observations will be made from outside the quadrat, looking in. Establish a route to take between the quadrats that will minimize disturbance near them. Use the Site Location form to record the location of each quadrat as thoroughly as possible, as relocating them can be extremely difficult, especially in the fall.

Spring Quadrat Sampling
Sampling in the spring will take place about three weeks after the beetles have emerged from their overwintering locations and resumed normal activity. At this time the loosestrife plants will be about one foot tall, on average. Fill out one data sheet for each purple loosestrife-infested wetland visited. If more than 5 quadrats are established at a location use two data sheets.

Record the location, date, time, weather conditions, temperature and the name(s) of the evaluators at the top of the data sheet. Approach the first sample quadrat slowly to avoid disturbing adults that may be present. You will spend one minute looking for adults, an additional minute looking for eggs, and one minute looking for larvae. If more than one person is collecting data, the minute spent looking for each life stage will be divided by the number of people. Do not attempt to observe more than one life stage during a one minute period.

Adults may be found anywhere on the plant but will most often be found feeding at the shoot tip. Count all the adults seen within the quadrat during the one minute interval and record the number. Next, count the number of larvae observed within one minute and record this number. Larvae can be found anywhere on the plant. Finally, spend one minute counting the number of eggs observed and include this number on the data sheet. Eggs may be found on any plant part including the undersides of leaves. Repeat these observations for the other quadrats.

The next measurements taken are plant observations. Record the percentage of the area within the quadrat occupied by purple loosestrife plants. To do this, visualize looking down at the quadrat directly from above. Estimate the percentage of the total ground surface which is covered by loosestrife (i.e. 0 to 100%). Using the frequency chart record the letter corresponding to the percentage of the total quadrat area occupied by purple loosestrife. Next, count and record the number of individual purple loosestrife stems within the quadrat. Galerucella feeding damage is assessed next. Use the frequency chart record the letter corresponding to the percentage of stems which show signs of feeding. Adult feeding produces holes in the leaves. Larval feeding strips the green layer of tissue from the leaves. Finally, measure and record (in centimeters) the height of the five tallest stems in the quadrat (from root crown to tip of plant).

Fall Quadrat Sampling
The quadrats will be visited again for data collection in the fall after plants have matured. The Galerucella beetles are not active in the fall so all data collected involves only the purple loosestrife plants.

Record the location, date, time, weather conditions, temperature and the name(s) of the evaluators at the top of the data sheet. The first observation to make is the percentage of the area within the quadrat occupied by purple loosestrife plants. To do this, visualize looking down at the quadrat from above, as before. Estimate the percentage of the total area in the quadrat covered by loosestrife and use the frequency table to choose the letter corresponding to the percentage. Next, count and record the number of individual purple loosestrife stems within the quadrat. For the next measurements it is important to keep all data for the same stem together. The best way to do this is to first measure and record the height (in centimeters) of one of the five tallest stems. Next, for that stem, count and record the number of inflorescences. The inflorescence is the part of the stem containing the flower buds. The next step is to measure and record the length in centimeters of the terminal inflorescence fothat stem. The terminal inflorescence will be the one which is uppermost on the stem compared to the others. Repeat this procedure for the other four stems being careful to keep individual stem information together.

Click here to get to download the Spring Data Collection Form in PDF format (80k) or MS Word document (36k).

Click here to get to download the Fall Data Collection Form in PDF format (68k) or MS Word document (36k).