Publications:
- Research papers:
1. Dimitrov, D., H. Kontev, I. Lecheva, 2006, Investigations on harmful and beneficial entomofauna in field peas under the conditions of Dobroudja region., Plant science, Vol. 43, ¹ 5 : 387-391 (in Bulgarian)
Abstract: Results are given from the
investigation on harmful and beneficial entomofauna in field spring peas under
the conditions of Dobroudja region. The studies were carried out during 2004 and
2005 in the trial field of Dobroudja Agricultural Institute- General Toshevo.
Classical methods of entomology were used to establish the specific composition
of field peas entomofauna, the population numeral dynamics of preferential
harmful species and their entomophages under the regionally specific
environmental conditions, both abiotic and biotic. The following pests were
identified as preferential harmful insects of economic importance: Bruchus
pisorum (Linnaeus, 1758), Tychius quinquepunctatus (Linnaeus, 1758),
Containia pisi (Loew, 1850), weevils of the genus Sitona, pea thrips -
Kakothrips robustus (Uzel, 1895) and leaf aphids.
Among the entomophages parasites and predators were determined in the
individual species of aphids.
Key words: Pisum sativum, harmful and beneficial entomofauna
2. Dimitrov, D., I. Lecheva, H. Kontev, 2007, Amathes (Xestia) c-nigrum L. (Noctuidae: Lepidoptera) - a pest on some legumes and on sunflower in the region of Dobroudja., Acta Entomologica Bulgarica, Vol. 13, ¹ 1,2 : 98 - 110 (in Bulgarian)
Abstract: In 2006 noctuid (Amathes c-nigrum L.) caterpillars attack was registered in the region of Dobroudja Agricultural Institute - General Toshevo. Their density was determined through sampling plots, soil digging and reading on individual plants. Peas, vetch, Ientil, chickpea and sunflower crops were investigated. Highest numbers of the pest were found in vetch (24 caterpillars/m2) and in lentil (21,5 caterpillars/m2) crops. Attack by this pest on vetch and lentil is reported for first time in the region. Noctuid caterpillars were not found in the chickpea crop. The damages were most evident in the sunflower crop, a part of the plants being completely defoliated. A description of the caterpillars is given and the damages they caused.
3. Dimitrov, D.; H. Kontev; I. Lecheva, 2008, Investigations on harmful and beneficial entomofauna in common spring vetch under the conditions of Dobroudja region., Plant science, Vol. 45, ¹ 1: 11-15 (in Bulgarian)
Abstract: Results from the investigation on harmful and beneficial entomofauna in common spring vetch under the conditions of Dobroudja region have been discussed. The studies were carried out during 2004 and 2005 in the trial field of Dobroudja Agricultural Institute - General Toshevo. Classical methods of entomology were used to establish the species composition of spring vetch entomofauna, the population numeral dynamics of prevailing harmful species and their entomophages under the regionally specific environmental conditions, both abiotic and biotic. The weevils of genus Sitona, pea aphid - Acyrtosiphon pisum (Harris, 1776), black bean aphid - Aphis fabae (Scopoli, 1763), pea thrips - Kakothrips robustus ( Uzel, 1895) and leaf-mining flies of Agromyzidae family were identified as harmful species of economic importance on spring vetch. Among the entomophages on leaf aphids most numerous were the Coleoptera species - Rhagonycha fulva (Scopoli, 1763), Harpalus (Pseudoophonus) rufipes (Degeer, 1774), and the coccinellids Propylaea quatuordecimpunctata (Linnaeus, 1758) and Coccinula quatuordecimpustulata (Linnaeus, 1758). Species from genus Opius were detected parasitizing on the larvae of leaf-mining flies from Agromyzidae family.
4. Dimitrov, D., D. Atanasova, M. Mihov, 2009, Investigation on gram pod borer Helicoverpa armigera Hübn. (Noctuidae: Lepidoptera) attack in chickpea., Field Crops Studies, 2009, Vol. V, ¹1: 143 - 150 (in Bulgarian)
Abstract:
Gram pod borer is a main pest on chickpea which causes serious damages. One
of the means for control of it is developing resistant varieties. The aim of
this investigation was to study the response of different chickpea accessions to
this pest, as well as its attacking rate. The trial
was carried out in Dobrudzha Agricultural Institute during 2005-2006 by the
block design method, in four replicates, the size of the trial plot being 10 m2.
Five chickpea varieties and one line of different origin were tested. To
determine the flight dynamics of the pod borer moths, “Pherobank” pheromone trap
was used. Three plants per each replicate were chosen at random to find out the
percent of attack. During the first year of the investigation a higher number of
moths were caught with the pheromone trap in comparison to the second year. The
genotype had the highest effect on the percent of damaged pods. Its effect
amounted to 60 % according to the other factors: year and total number of pods.
Variation in the attacking rate by caterpillars of the pest during the two years
of the investigation was found. The percent of damaged pods in the individual
accessions varied within the range 0,6 – 11,56 %. The differences were most
evident during the first year when the pest occurred in higher density. Variety
Obraztsov chiflik was the most resistant; the attacking rate on this variety was
lowest during both years of investigation.
- Articles:
Beneficial and harmful entomofauna in some grain legumes
Dimitrov, D.,
2008, Beneficial and harmful entomofauna in some grain legumes.,
Ph.D Thesis., Dobroudja Agricultural Institute, General
Toshevo, Bulgaria, pages 166, In Bulgarian
Abstract:
Investigations on the harmful and beneficial entomofauna in
spring filed peas, common spring vetch, lentil and chick pea were carried out
during 2004-2006 at Dobroudja Agricultural Institute - General Toshevo.
Classical entomological methods were applied for determining
the species composition and the amount of the entomofauna in the legume crops:
pitfall traps, soil excavations, trial plots, colored sticky traps, pheromone
traps, sweep nets, collecting of pod and seed samples, and isolation of
parasites.
As a result from the investigation, insects from eight orders
of Insecta class were identified: Coleoptera, Hemiptera, Hymenoptera, Diptera,
Neuroptera, Orthoptera, Thysanoptera and Lepidoptera.
Highest specific variability was found in spring vetch - 116
species from 97 genera of 42 families. In lentil 111 species from 94 genera of
40 families were identified. Chick pea ranked third by specific variability -
104 species from 84 genera of 40 families. Lowest specific variability was
registered in spring field peas - 91 species from 80 genera of 34 families.
The dominant harmful species in field peas were
Acyrthosiphon pisum (Harris, 1776), Sitona macularius (Marsham,
1802), Bruchus pisorum (Linnaeus, 1758), Tychius quinquepunctatus
(Linnaeus, 1758) and Kakothrips robustus (Uzel, 1895).
In common vetch the dominant species were Aphis fabae (Scopoli, 1763),
Aphis craccivora (Koch, 1854), Empoasca pteridis (Dahlbom, 1850),
Sitona macularius (Marsham, 1802), Tychius quinquepunctatus
(Linnaeus, 1758), Kakothrips robustus (Uzel, 1895) and the leafminer
flies from Agromyzidae family.
The dominant harmful species in lentil were the following:
Aphis fabae (Scopoli, 1763), Aphis craccivora (Koch, 1854),
Empoasca pteridis (Dahlbom, 1850, Sitona macularius (Marsham, 1802),
Tychius quinquepunctatus (Linnaeus, 1758), Bruchus lentis (Frölich,
1799) and Kakothrips robustus (Uzel, 1895).
The leafminer flies from Agromyzidae family, Kakothrips
robustus (Uzel, 1895), Helicoverpa armigera (Hübner, 1808) and
Empoasca pteridis (Dahlbom, 1850) were predominant in chick pea.
The beneficial insects were 5.6 - 31.4 % of the total amount
of insects swept with the entomological net.
Among the beneficial entomofauna, the Coleoptera predators
and the Hymenoptera parasites were most numerous.
Finally, the biology, the population dynamics, and the
harmful activity of pea weevil Bruchus pisorum L., vetch weevil
Bruchus atomarius L., lentil weevil Bruchus lentis F., the weevils of
genus Sitona, the five-pointed little long-nose Tychius quinquepunctatus
L., the pea midge Contarinia pisi Loew, the leafminer flies of
Agromyzidae family, and of the noctuids Helicoverpa armigera Hüb. and
Xestia c-nigrum L. were considered.
