Appendix A: Troubleshooting Guide; When things go Wrong
Wilson, L.M. and Randall, C.B. 2005. Biology and Biological Control of Knapweed. USDA Forest Service FHTET-2001-07. 3rd Edition. 110 p.
This guide is intended to assist those who encounter problems when establishing a biological control program. It identifies the probable cause of a typical problem and offers solutions.
|Bioagents unhealthy||Physical damage to agents||Prevent containers from colliding; use crush-proof containers.|
|Drowning||Do not put water in containers. Prevent acumulation of excess moisture in the collection containers.|
|Excess or prolonged heat or cold||Keep containers cool at all times; use coolers and blue ice packs; avoid exposure to direct sunlight while in transit.|
|Starvation||Put knapweed foliage (no flowers, seeds, or roots) in containers.|
|Redistribution time||Transport or ship agents immediately after collection.
Release agents at new site immediately upon arrival or receipt of agent.
|Parasitism and/or disease||Check source agents. Ensure the insect population is disease-free when collecting or receiving shipment.|
|Number of eggs low||Agents past reproductive stage||Collect at times of peak activity (i.e., insects are mating).|
|Sex ratio: not enough males or females||Observe mating among bioagents before collecting; males often emerge earlier than females.|
|Synchrony||Agents not synchronized with the knapweed growth stage; bioagnets require knapweed to be at specific growth stage for optimal oviposition.|
|Few bioagents collected||Wrong method used||Refer to Tables 11 and 12 for recommended collection time and technique.|
|Collection done at wrong time||Refer to Tables 11 and 12 for recommended collection time and technique.|
|Collection technique||Bioagents can be killed during sweeping or aspirating.
Use vacuum aspirator if aspirating by mouth is not working. Practice sweeping.
|Conditions at time of collection wrong||Refer to "Collecting Biocontrol Agents" and "Monitoring Biocontrol Agents" for guidelines on desirable weather conditions.|
|Agents not found after release||Site is unsuitable||Refer to "Collecting Biocontrol Agents."|
|Site too small||Select a larger site with a dense, uniform stand of knapweed.|
|Pesticide used in area||Select pesticide-free site.|
|Cannot locate release site||Permanent location marker not obvious||Use bright-colored wooden, metal, or plastic stake.|
|Map poorly or incorrectly drawn||Check map; redraw with more detail or add landmarks.|