Plamen Mirchev

The Egg Parasitoids of Thaumetopoea pityocampa in the Atlas Mountains near Marrakech (Morocco)

Studies were performed on 25 egg batches ofThaumetopoea pityocampa (Den. & Schiff.) collected onPinus pinaster Ait. on 29. XI. 1995, in the Atlas Mountains of Morocco near Marrakech at 1400-1800 m above sea level. All the egg masses had been deposited in the autumn of 1995 and were exposed to the parasitoids throughout the developmental period of the host. In 1996, the egg batches, kept singly in test tubes, were observed almost daily. Emerged parasitoids were recorded and separated. The final analyses were made in November 1996 based on the meconia and remains of the emerged or the dead parasitoids in the eggs. In all cases, oviposition occurred from the base to the tip of the needles, distances varying up to 62 mm from the base. The mean number of eggs per batch was 175 (range 34-245), the number of egg-rows varied between 6 and 11, and a 1-cm egg-row contained a mean of 9 eggs. Caterpillars hatched from 72. 7% of the eggs; total mortality of the eggs was thus 27. 3%. The impact of egg parasitoids was 21. 4%. Most of the parasitized eggs were attacked byBaryscapus servadeii (Dom.) followed byOoencyrtus pityocampae (Mercet). Males (1. 5%) were found only in B. servadeii. The emergence rate ofO. pityocampae was much higher in the year of host oviposition than in the following year. B. servadeii emerged in equal numbers before and after hibernation, and in the subsequent year in equal numbers in spring and autumn. The high rate of emergence ofB. servadeii in April-May is discussed in relation to the embryonic development ofThaumetopoea bonjeani (Powel) until the end of winter, as an alternative host ofB. servadeii in the Atlas region.

Monitoring the establishment and prevalence of the fungal entomopathogen Entomophaga maimaiga in two Lymantria dispar L. populations in Bulgaria

The establishment and prevalence of the entomopathogenic fungus Entomophaga maimaiga, (Zygomycetes, Entomophthorales), introduced into two gypsy moth populations in Bulgaria, was monitored during 2000–2004. In the Karlovo Region population, where E. maimaiga was introduced in 1999, the fungus was recovered every year and the prevalence of infection varied from 6.1% to 15.9%. A microsporidian infection caused by an Endoreticulatus sp. (Protista, Microsporidia) was also recorded every year and the prevalence varied from 2.1% and 5.0%. In the Svoge Region population, where E. maimaiga was introduced in late 2000 and first found in 2002, the prevalence of infection varied from 8.8% to 13.8%. Larval parasitism caused by Cotesia melanoscela, Protapanteles liparidis (Hymenoptera, Braconidae) and species of tachinids (Diptera, Tachinidae) was also recorded in the larvae of both populations. We provide a rationale as to why other countries should consider introducing E. maimaiga for biological control of Lymantria dispar populations.

Entomophaga maimaiga – New entomopathogenic fungus in the Republic of Serbia

The higher mortality rate of the older gypsy moth larval instars was reported in the forest complexes of Belgrade and Valjevo region, in the culmination phase of the new outbreak of the gypsy moth in Serbia. By field and laboratory studies of the causes of their death, the presence of conidia and resting spores of the entomopathogenic fungus Entomophaga maimaiga was reported in the dead caterpillars. This has been the first report of occurrence of this species in Serbia, that is, Serbia is the third European country in which this fungus has been reported. It showed to be a powerful reducer of the population size of the gypsy moth, and in both regions it caused the collapse of the outbreak in 2011. Keywords: Entomophaga maimaiga , Lymantria dispar , gypsy moth, biological control, epizootics

Interactions between the introduced fungal pathogen Entomophaga maimaiga and indigenous tachinid parasitoids of gypsy moth Lymantria dispar in Bulgaria

Interactions between the gypsy moth, Lymantria dispar L. (Lepidoptera: Erebidae), pathogenic fungus Entomophaga maimaiga, and the tachinid parasitoid (Diptera: Tachinidae) complex in gypsy moth larvae were investigated in Bulgaria, where E. maimaiga was recently released as a biological control agent. Gypsy moth larvae were collected in oak stands where E. maimaiga was originally introduced (nine sites) and in sites where the pathogen has invaded by natural extension of the range (ten sites). In total, 4,375 host larvae were examined and 401 tachinid larvae emerged from parasitized hosts. Host mortality caused by tachinids varied from 0 to 48.5% among sites, with an overall average of 9.2%. Emerging adult tachinid parasitoids included 54 individuals belonging to six species: Compsilura concinnata, Exorista larvarum, Senometopia separata, Senometopia excisa, Drino incospiqua and Zenilia libatrix; the remaining parasitoids (86.5%) died in the pupal stage. E. maimaiga azygospores were observed on puparia surfaces, an indication that the gypsy moth host larvae were infected with the fungus. No azygospores were observed in parasitoid tissues. The high parasitoid mortality may be the result of the competition with E. maimaiga during development in the same host.

POTENTIAL OF ENTOMOPHAGA MAIMAIGA HUMBER, SHIMAZU AND SOPER (ENTOMOPHTHORALES) FOR SUPPRESSING LYMANTRIA DISPAR (LINNAEUS) OUTBREAKS IN BULGARIA

The Asian fungal entomopathogen Entomophaga maimaiga was first introduced in Bulgaria for biological control of gypsy moth, Lymantria dispar, in 1999 and the first epizootics in gypsy moth populations were observed in 2005. Six introductions of E. maimaiga in oak forests with heavy L. dispar infestations were conducted from 2008 to 2011 in different regions of the country, including Nova Zagora, Gorna Oryahovitsa, Popovo, Targovishte and Staro Oryahovo. As a result of these introductions, host density was decreased by 55.1–100% and the outbreaks were suppressed. After the introduction of the pathogen in Bulgaria, no microbiological or chemical control of L. dispar has been necessary and the last two gradations have been estimated to be 15–30% of the values in previous gradations.