The cannabis plant is not demanding for cultivation, it withstands modest conditions for the habitat, has few natural enemies, grows quickly and with a large yield. However, we cannot say that he has no enemy. And even these few enemies can make big problems. Let's take a look at what are the most common natural enemies of cannabis.
Hemp after emergence, especially in dense sowing, with quick cover, does not allow weeds space and light, so after harvest, the field is clean and with good structure. Mechanical control of weeds by weeding, two to three times manual or machine hoeing is only suitable for rare sowing when the purpose is to produce seeds, e.g. for oil or the next sowing.
The most dangerous weeds: spinach (Cuscuta epilinum Weihe), harmful hemp and flax sheath and willow or overgrowth (Orobanche ramosa Dum.). The stems of the wormhole stick into the hemp stem, destroying the fiber quality and obstructing harvesting. In the next crop, the spinach and the kettle feed mostly on the homegrown seed. We will not find them for the purchased seeds, because their seeds are removed with a special cleaning method.
Appears on the leaves, especially during drought years. The signs of the infection are round, dark-grayish spots, which are streaked with tiny black dots. However, chemical density is not appropriate for sowing density and height of the stems themselves. The only virus of cannabis is the viral infection of hemp leaves. Typical discoloration of the leaves spreads between the leaf veins. The leaves of the leaf margin turn inwards and the leaves roll. The virus is transmitted by infected leaf juice, and the carriers are lice from the genus Diphorodon cannabis Pass. As the transmission of infections through semen is also proven, the only way to control sowing healthy, uninfected seeds is.
Young plants can be damaged by fleas (Psyllioides attenuata Koch), owls (Agrotis sp.), Maize (Ostrinia / Pyrausta / nubilalis Hbn.) And stem nematode (Ditylenchus dipsaci (Kulm.) Filip.). Hemp wrapper (Grapholita delineana Walk.) It can cause considerable damage. Rotated into stems, it eats holes, leaving distinct thickening at the point of the incursion. The quality of the fibers is reduced and the seed yield, which feeds on caterpillars, in particular, is reduced. A wrap has many shapes and can form multiple genera in one year. Cannabis extracts leaf juice and causes leaf curl and curl, red coloration and drying (Phorodon cannabis Pass.). Aphids of this species live only on hemp, and like other aphids, they congregate into groups on the underside of leaves. More severe lice attacks usually begin in August.
Due to similar diseases and pests that infect or attack hops, it is not advisable to sow cannabis near hops.
Birds can also exclude many seeds sown, so we can protect the crop at the beginning with mechanical or chemical deterrents. Birds are again harmful during the period of seed maturation and maturity.