Biological control of gypsy moth (Lymantria dispar) by the entomopathogenic fungus Entomophaga maimaiga in Bulgaria in 2021

In 2021, biological control programme against gipsy moth (Lymantria dispar) populations was carried out by introduction of the entomopathogenic fungus Entomophaga maimaiga on the territory of four State Forest Enterprises: Municipal Enterprise (ME) ‘Management of Municipal Forests, Agriculture and Forestry’, Nessebar; State Game Enterprises (SGE) Nessebar and Balchik; State Forestry (SF) Vidin. The pathogen was introduced during the period 15-26.03.2021 in 34 localities - five in ME Nessebar, eight in SGE Nessebar, ten in SGE Balchik and eleven in SF Vidin. The average number of gypsy moth population density in the locations of introduction was relatively high, ranging between 0.4-15.9 egg mass/tree in the area of ​​SGE Balchik and 11.9-65.0 egg mass/tree in the area of ​​ME Nessebar. The average mortality of young gypsy moth caterpillars (first-third instar) due to E. maimaiga varied between 2.6% (SGE Balchik) and 13.0% (SF Vidin), and of caterpillars in later fourth-sixth instar - between 20.7% (SF Vidin) and 52.4% (ME Nessebar). The overall mortality of the gipsy moth caterpillars due to E. maimaiga was lowest in the region of SGE Balchik (26.1%), followed by SF Vidin (33.7%), SGE Nessebar (48.5%) and ME Nessebar (55.9%). As a result of the introduction, gipsy moth severe outbreaks in the region of Nessebar was significantly suppressed. The high number of E. maimaiga resting spores persists in the surface layers of the soil in the other two areas (Vidin and Balchik) has the potential to suppress L. dispar attacks in next years.

Spore viability of microsporidian species isolated from gipsy moth larvae (Lymantria dispar) after long-term storage in liquid nitrogen

U radu se prikazuju rezultati preživljenja mikrosporidija izoliranih iz gubara (Lymantria dispar) nakon dugotrajne pohrane u tekućem dušiku. Infektivnost osam mikrosporidijskih L. dispar izolata testirano je na ličinkama gubara: Vairimorpha disparis, Nosema lymantriae, Nosema portugal, Nosema sp. (Poljska), Nosema sp. (Ebergassing), Nosema sp. (Njemačka), Nosema sp. (Schweinfurt) and Nosema sp. (Veslec). Preživljenje spora u tekućem dušiku detaljno je praćeno kod N. portugal i Nosema sp. (Ebergassing) koje su tako čuvane skoro 19 godina i aplicirane oralnom infekcijom i ponaosob na svaku pojedinu ličinku gubara. Ostalih 6 izolata aplicirano je površinskom kontaminacijom hranjivog supstrata, također oralnim infekcijskim putem. Od 8 mikrosporidijskih izolata apliciranih površinskom kontaminacijom samo kod 4 izolata, Vairimorpha disparis, Nosema lymantriae, Nosema sp. (Ebergassing) i Nosema sp. (Poljska), došlo je do uspješne infekcije ličinki gubara. Dok je kod svih testiranih ličinki (100%) uspješno realizirana infekcija sporama prve tri mikrosporidije, tek 21,1% tretiranih ličinki uspješno je inficirano sporama Nosema sp. (Poljska). Na kraju inkubacijskog razdoblja, kod svih ličinki inficiranih sa sva 4 izolata disekcijom je utvrđen visok stupanj zaraze; tkiva su bila ispunjena sporama. Mikroskopska pretraga ličinki L. dispar individualno tretiranih sporama Nosema portugal uz tri različite doze (100, 1000 i 10000 spora) pokazala je da su spore N. portugal izgubile infektivnost nakon 19 godina pohrane u tekućem dušiku; niti jedna od testiranih ličinka nije bila zaražena. Naprotiv, spore Nosema sp. (Ebergassing) zadržale su infektivnost nakon istog razdoblja pohrane u tekućem dušiku od 18,75 godina. Niti jedna od testiranih ličinki nije zaražena nakon oralnog unosa od 100 spora. Oralna aplikacija od 1000 spora po ličniki rezultirala je ukupnom uspješnom infekcijom 4,1% ličinki, a aplikacija od 10000 spora s 68,8% inficiranih ličinki. U svim uspješnim slučajevima uspješno zaraženih ličinki, na kraju inkubacijskog razdoblja infekcija je bila dobro razvijena, a masno tijelo prepuno spora. Istraživanje je potvrdilo da je pohrana mikrosporidija Nosema i Vairimorpha vrsta i domaćina iz reda leptira prikladna opcija za dugotrajno čuvanje izolata. Spore su preživjele i do 18 i pola godina, iako je tijekom eksperimenta zamijećen i značajan pad njihove infektivnosti. U pojedinim slučajevima spore su odumrle već nakon 7 godina pohrane u tekućem dušiku. Preporuka je da prilikom skladištenja i pohrane mikrosporidijskih izolata u tekućem dušiku svakih 5 godina repozitorij obnavlja svježim izolatima. Materijal koji se dulje vrijeme skladišti u tekućem dušiku nije prikladan i ne bi se smio koristiti u infektološkim testovima.

Pyrrolidonyl and Pyridyl Alkaloids in Lymantria dispar

The occurrence and metabolism of nicotine and related N-containing compounds in body fluids of the gipsy moth were addressed. Thin layer chromatographic studies clearly showed the simultaneous presence of GABA and 2-pyrrolidone but not of GABamide in the larval haemolymph and osmeterial secretion of Lymantria dispar as well as in the corresponding body fluids of the saturniids, Saturnia pavonia and Attacus atlas. Furthermore, feeding and injection experiments using alkylated precursors and combined gas chromatography/mass spectrometry gave evidence of the transformation of 2-pyrrolidone to nicotine and of nicotinic acid to nicotinamide in caterpillars of L. dispar. Based on these results, on the earlier described variation of the secondary-compound patterns of L. dispar during its development, and on literature data, metabolic pathways for the hitherto detected pyridyl and pyrrolidonyl alkaloids in Lymantriidae (and possibly Saturniidae) are proposed.

Pochonia suchlasporia. [Descriptions of Fungi and Bacteria].

A description is provided for Pochonia suchlasporia. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Both varieties parasitize nematode eggs, rarely insect larvae. HOSTS: NEMATODA: var. suchlasporia: Heterodera spp., more rarely Globodera rostochiensis (DACKMAN 1990); var. catenata: also Heterodera avenae (ZARE et al., 2001). INSECTA: Lymantria dispar (gipsy moth, Lepidoptera) (CARROLL, 1987, as Verticillium coccosporum; ZARE et al., 2001). Also isolated from soil. GEOGRAPHICAL DISTRIBUTION: Mainly temperate (EUROPE, NORTH AMERICA: USA, Canada) but also reported from Cuba (HIDALGO-DIAZ et al., 2000). TRANSMISSION: Soil- and air-borne.

Lymantria dispar. [Distribution map].

A new distribution map is provided for Lymantria dispar (L.) (Porthetria dispar(L.)) (Lep., Lymantriidae) (Gipsy Moth). Host Plants: Oaks, deciduous forests and fruit trees. Information is given on the geographical distribution in EUROPE (excl. USSR), Austria, Balearic Islands, Belgium, Bulgaria, Corsica, Czechoslovakia, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Poland, Portugal, Romania, Sardinia, Sicily, Spain, Sweden, Switzerland, Yugoslavia, ASIA (excl. USSR), Afghanistan, China, Cyprus, India, Iran, Iraq, Israel, Jammu, Japan, Korea, Lebanon, Ryukyu, Syria, Taiwan, Tibet, Turkey, USSR, AFRICA, Algeria, Morocco, Tunisia, NORTH AMERICA, Canada, USA.