Not knowing much about these thugs ourselves, we had to do some research and the following is some of what we found.
Nematodes or roundworms are diverse and are found all over the world. Root-Knot Nematodes infect some 2000 plants and they cause approximately 5% of global crop loss. The larvae infect plant roots, causing the development of root-knot galls that drain the plant's energy and nutrients. They are tiny, microscopic actually. Ways of control include chemicals, crop rotation, cover crops, and biological control.
|Root Nematode Damage|
Carrot Rust Fly larvae feed on the root of the carrot. Foliage becomes wilted and discolored and rusty brown tunnels are seen in the root. The flies lay their eggs around the developing carrots, the larvae, once hatched, burrow into the root. Because female carrot flies are low flying, the best method of prevention is to erect a barrier at least 2 feet high. Other control methods include using row covers, or planting rosemary, sage, and marigolds. Some newer varieties of carrot claim to be resistant.