Ivelina NIKOLOVA1*, Natalia GEORGIEVA1
1Department Tehnology and ecology of forage crops, Institute of Forage Crops, Pleven, BULGARIA
*Corresponding author email@example.com Tel. +359 884684575
Abstract. One of the most serious pests of commercial Fabaceae crops especially alfalfa is the pea aphid Acyrthosiphon pisum Harris. The pea aphid damages crops directly caused chlorosis and necrosis, leading to significant alfalfa loss worldwide. Hence the need for aphid management and use of insecticides. It was studied the effect of a biological insecticide Agricolle and two biological nano–fertilizers (Nagro and Lytovit) to a control of pea aphid, Acyrthosiphon pisum (Hemiptera, Sternorrhyncha: Aphididae) and changes in plastid pigment and total nitrogen contents in alfalfa. On the basis of the sweeping with the entomological net average number of aphids and mortality were calculated on the 1, 5, 7 and 9 days after treatment. It was found that the treatment with biological products Agricolle, Nagro and Litovit used alone and in combinations reduced Acyrthosiphon pisum density in a different range. After application of Agricolle with Nagro combination, followed by Agricolle was found the lowest density and the highest aphid mortality. Biological products increased the total pigment content as the highest impact demonstrated used of Agricolle with Nagro–33.4 % increase, followed by treatment with Nagro–29.6 %. Chlorophyll a to chlorophyll b as well as green pigments to carotenoids ratio determined plants treated with Agricolle + Nagro and Nagro as plants with the best physiological state. Alfalfa fixed the most nitrogen (respectively more with 2.77 and 2.95 kg N/kg dry mass yield in compared to control) in the combined treatment of Aricolle with Nagro and Litovit.
Keyword: Agricolle, nano–fertilizers, Acyrthosiphon pisum, mortality, plastid pigments, nitrogen.