BIOLOGICAL CONTROL OF PEPPER TREE PSYLLID. FINAL REPORT

In 1987, a biological control program was initiated against the pepper tree psyllid (PTP), Calophya schini, which attacks the California pepper tree, Schinus molle. This psyllid was first discovered in California in Los Angeles County in 1984, and subsequently spread to most trees along coastal California. Since the California Department of Transportation (CALTRANS) has planted many pepper trees along the freeways and because CALTRANS has the philosophy of keeping the use of pesticides to a minimum by advocating the biological control approach, we proceeded to use the classical approach of biological control. Since the PTP originated in Chile or Peru, a search was made in Chile, and a parasitic wasp, Tamarixia sp., was found and tested in quarantine and released in California. It quickly spread from the release sites and readily attacked the PTP in both northern and southern California. If there has been a reduction in psyllid abundance due to activity of the parasite, it has been obscured by the high seasonal variation of psyllid populations. However, since the pests and natural enemies react in constantly-changing environments, it may be too early to give the final word on the parasite's effectiveness. For this reason, and in view of the fact that current threats to the pepper tree from the psyllid appear to be minimal, it is important to avoid pesticide use in the system.

• Corporate Authors:

  California Department of Transportation

  Transportation Laboratory
  5900 Folsom Boulevard
  Sacramento, CA  United States  95819

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Hagan, K S
  • Tassan, R L
• Publication Date: 1993-6

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 24 p.

Subject/Index Terms

• TRT Terms: Biological control; Measures of effectiveness; Pest control; Roadside; Trees
• Uncontrolled Terms: Effectiveness
• Geographic Terms: California
• Subject Areas: Design; Environment; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00636380
• Record Type: Publication
• Report/Paper Numbers: FHWA/CA/TL-94/03, Rept 56-650-627152
• Contract Numbers: E88HM03
• Files: TRIS, USDOT, STATEDOT
• Created Date: Sep 20 1996 12:00AM