Screening of plant protection products against downy mildew on cucumbers (Pseudoperonospora Cubensis (Berkeley & M. A. Curtis) Rostovzev) in cultivation facilities

S. Masheva, N. Velkov, N. Valchev, V. Yankova
Abstract. Screening of plant protection products (PPP) against downy mildew in cucumbers Pseudoperonospora cubensis (Berkeley & M. A. Curtis) Rostovzev was carried out during the period 2006-2011 in the “Maritsa” Vegetable Crops Research Institute, Plovdiv. Their toxicity to the imago of the bioagent Encarsia formosa Gah. were studied. High effectiveness (over 85.00 %) of the PPP with active ingredients: dimethomorph (Zampro SC, Acrobat paplus SC); symoxanil (Korsate Pro WG, Korsate R DF), strobilurins (Eclair 49 WG, Quadris 25 SC) was established. With the lowest effectiveness to the agent of downy mildew is Timorex 66 EC. All studied products are suitable for including in the systems for control of this disease. A non-toxic product to E. formosa is the botanical fungicide Timorex 66 EC, medium toxic products are those containing a.i. strobilurin and propamocarb-hydrochloride. The remaining PPP are slightly or medium toxic to the bioagent. Therefore E. fоrmosa could be applied parallel with slightly toxic fungicides against P. cubensis.

Plant species screening for biofumigant activity against soil-borne pathogens and root-knot nematodes

S. Masheva, V. Yankova, G. Toskov
Abstract. During the period 2009-2010 in the Maritsa Vegetable Crops Research Institute, Plovdiv in pot experiments screening was conducted for biofumigation activity of five plant species (chrysanthemum, broccoli, tagetes, basil and marigolds in the rate of 4 kg/m2). Herbage (50 days) was introduced in August in soil infested with Verticillium dahliae and Meloidogyne arenaria. The containers were covered with polyethylene film. The maintained humidity is 75- 80% and soil temperature – 37,8º C – 45,5º C. On the following year pepper plants (variety Kurtovska kapiya1619) were planted in pots with pathogen and tomatoes (variety Ideal) in pots with nematode. All testing plants species showed activity towards the verticillium wilt and nematodes. The Neal highest efficacy against Verticillium dahliae Kleb. is reported in variants with plant residues of chrysanthemum (E=76,11%) and broccoli (E=71,99%), and against Meloidogyne arenaria – with broccoli (E=71,23%), chrysanthemum (E=67,68%) and tagetes (E=64,79%).