It is result of damage by carrot fly. Length of an adult carrot fly is 4 - 5 mm. A paunch of a carrot fly oval, is brilliant-black, a head brownish-red with a black triangular stain. Larvae of a carrot fly thin, light yellow, legless, length to 7 mm. Pupa of a carrot fly winters in follicle in soil, is more rare - larvae in root crops in storehouses. The emergence of carrot flies coincides with apple-tree flowering. Females of carrot flies lay eggs near fodder plants on soil. Larvae get into a root crop, making in it tunnels. Leaves at such plants become red-violet, soon turn yellow and dry up. In a midland develops two generations. It is noticed that the potato and semilong grades of carrots are damaged more strongly.
Preventive measures against carrot fly:
- It is necessary to place carrots far away from those sites where it grew up last year,
- Carefully to dig over soil (it complicates a emergence of carrot flies in the spring),
- To sow seeds in early terms,
- It is necessary to thin out in due time plants as densified crops are damaged more strongly.