Overwintering Stage: If is a mild winter, the adult is able to survive under snow, but they primarily overwinter as eggs on winter foliage. (1)
Egg Stage: The adult can end up laying about 2000 tiny, 1.2 mm x 0.5 mm, reddish eggs. The eggs are either laid in either tiny clusters or individually. They can be laid in the spring or winter foliage. In Canada they are usually laid in the spring. (1, 3)
Larval Stage: When entering the larval stage, they turn hump shaped and orangish then later a grayish color. This stage is not often seen because sunlight is absorbed by the larval hypericin and it kills the larvae so the larvae stay hidden. About 45 min. before sunrise the larvae will start feeding and then about 3 hours later they would disappear. Finally they reappear sometime around sunset. While the smaller larvae hide in the flower buds, you will find the larger ones in the roots of the plant. (1, 2, 3)
Pupil Stage: In the springtime, they finally start to pupate on the soil. On hard ground, they are not able to pupate. (1,3)
Adult Stage: On the underside of St. Johnswort blooms is where you will find the clusters of feeding adults. Finally they return to the soil and come back up in the fall, early June, again to lay their eggs and continue feeding. The life span of the adult is unknown. (1,2,3)
Type of Damage to Host:
Host: St. Johnswort (1)
Larval Stage: Within the 3 years as the beetles are increasing the consumption of St. Johnswort, it causes the stems of the plant to go from 100% to 1%, but this may take up to 10 years. (1,3)
Adult Stage: The defoliation that adults cause is more interesting but less effective. They are ineffective in moist, summer sites in British Columbia around a 1000m elevation. (1,3)
Favorable/unfavorable release habitats: The overwintering adults lay their eggs in springtime. They tolerate cooler and moist summers. They also do well in cold, little or no snow winters, but they do not do well in the shade. (1)
How and where to collect, transport, and release: You are able to shake the plants and collect them in either a sweep net or funnel cup/container. Sometimes you can end up collecting dozens from just one plant. The are also found in the blooms of St. Johnswort. Transporting is really easy because you just put the beetles into some sort of container or even a cooler and when you release them, just take them to your infested area of choice and dump them all out together. (3)
How to Redistribute Once Established: They can be redistributed to an area by being hand-picked or sweep netted (or see above). The beetles are able to be held in cool storage for several weeks and in transit for several days without ill effects. (1)
Where and How to Purchase: You can purchase the Klamath weed beetle at different sites. You can purchase 150 beetles for $75.00. (4)
The adult Chrysolina hyperici are smaller than the Chrysolina quadrigemina. They also start to come out in the later months of fall and their structure is also harder.
2. Agrobiologicals Website CPL Scientific Publishing Services, www.agrobiologicals.com, Ltd Suite 36 Liberty House, The Enterprise Centre New Greenham Park, Newbury RG19 6 HW, UK.
3. Norman E. Rees, Paul C. Quimby Jr., Gary L. Piper, Eric M. Coombs, Charles E. Turner, Neal R. Spencer and Lloyd V. Knutson, Biological Control of Weeds in the West.
4. Biological Control of Weeds, Inc., http://www.bio-control.com/pricing.asp
http://www.bio-control.com/pricing.asp, 1418 Maple Drive • Bozeman, MT
59715, Phone 406-586-5111 FAX: 406-586-1679.