Weeds
Spotted knapweed has a long root system that allows it to firmly entrench itself into the ground. Even though its egg-shaped flowers are decorative and attractive to pollinators, this plant can spread aggressively and is widely considered an invasive species.
How to Control it
It is best to remove spotted knapweed before flowering, so it cannot produce seeds and spread further. Repeated mowing and tilling are necessary in fields where this plant has already established. Manual pulling can be effective only with small scale infestations. Some people are sensitive to certain chemicals present in spotted knapweed, so it is advised to wear gloves when handling this plant. Larvae of sulfur knapweed moth (Agapeta zoegana) and knapweed root weevil (Cyphocleonus achates) eat the plants' roots, so they can be used for biological control. Knapweed peacock fly (Chaetorellia acrolophi) larvae can also be used, as they consume the seeds of spotted knapweed. This plant can also be controlled with herbicides. If you opt for this method, consult an agricultural expert beforehand to find the best active substance for your geographic region. Spray on a windless day to avoid drift.