Chemical control has emerged as the most efficient method of weed control. Herbicides combinations and tank mixtures of herbicides with adjuvants, fertilizers, growth regulators, fungicides, insecticides are more effective than when applied alone on sorghum crops. Their combined use often leads to high synergistic effect on yield. The use of herbicide antidotes for the treatment of seeds in sorghum is a safe way to overcome its high sensitivity to many herbicides. Data regarding herbicide for chemical control of annual graminaceous weeds in sorghum crops are quite scarce even worldwide. Problem is the persistence of some herbicides used in the predecessors on succeeding crops, which is directly related to the weather conditions during their degradation. Most of the information on sorghum relates to the conventional technology for weed control. There is no information about the new Concep technology in grain sorghum. A serious problem is also the volunteers of the Clearfield and Express sun sunflower. They have resistance to herbicides different from that of conventional sunflower hybrids. There is no information yet in scientific literature on control of these volunteers.

No abstract

Problems and achievements of cotton (Gossypium HirsutumL

For the first time in the world we established that the highest protein content in seeds of cultivar Helius was obtained with vegetative treatment with herbicides Goal 2 E, Linuron 45 SC, Wing P and Merlin 750 WG. The highest protein content in seeds of cultivar Darmy was obtained with vegetative treatment with herbicides Goal 2 E, Wing P and Basagran 480 SL. The highest phytotoxicity on protein content in seeds of cultivar Helius was shown by the herbicide Basagran 480 SL and all herbicide combinations with the growth regulator Amalgerol and the foliar fertilizer Lactofol O. The strongest phytotoxic effects on seeds of cultivar Darmy was produced by the herbicides Linuron 45 SC and Merlin 750 WG and herbicide mixture Wing P + Lactofol O. For the first time, we established that, from the point of view of the technology for cotton growing of cultivar Helius, the most valuable are tank mixtures Goal 2 E + Amalgerol, Linuron 45 SC + Amalgerol, Goal 2 E + Lactofol O, as well as the single use of herbicides Goal 2 E, Linuron 45 SC, Wing P and Merlin 750 WG. Technologically the most valuable in cotton cultivar Darmy were herbicide combinations Goal 2 E + Amalgerol, Wing P + Amalgerol, Merlin 750 WG + Amalgerol, Basagran 480 SL + Amalgerol, Goal 2 E + Lactofol O, Linuron 45 SC + Lactofol O, Merlin 750 WG + Lactofol O and Basagrain 480 SL + Lactofol O, and the herbicides Goal 2 E, Wing P and Basagran 480 SL.

The trial was carried during period 2013-2015 with twelve Bulgarian cotton cultivars - Chirpan-539, Helius, Trakia, Viki, Filipopolis, IPK-Veno, Boyana, Avangard, Natalia, Darmy Dorina and Nelina (Gossypium hirsutum L.). Herbicides Bazagran 480 SL (bentazone), Pulsar 40 (imazamox) and Express 50 SX (tribenuronmethyl), applied during budding stage of cotton, were investigated. For the first time in the world, cotton cultivars resistant to herbicides Basagran 480 SL, Pulsar 40 and Express 50 SX were identified. Herbicide Bazagran 480 SL had the highest phytotoxicity on seed germination in cultivars Chirpan-539. Herbicide Pulsar 40 had the highest phytotoxicity on seed germination in cultivar Filipopolis. Herbicide Express 50 SX had the highest phytotoxicity on seed germination in cultivar Chirpan-539. From the viewpoint of technology for cotton growing, in terms of its impact on germination of cotton seeds, technologically the most suitable to foliar treatment with herbicide Bazagran 480 SL are cultivars Helius, Trakia, Viki, Filipopolis, IPK-Veno, Boyana, Avangard, Natalia, Darmy Dorina and Nelina. For the first time in the world we established that in the vegetative treatment with herbicides, technologically the most suitable to foliar treatment with herbicide Pulsar 40 are cultivars Helius, Trakia, IPK-Veno, Boyana. Technologically the most suitable to foliar treatment with herbicide Express 50 SX are cultivars Filipopolis, IPK-Veno, Avangard, Natalia and Dorina. These variants combine high levels of the seed germination and high stability of this index during the years.