Protejarea fructificaţiei laricelui european (Larix decidua Mill.) împotriva insectelor conurilor şi seminţelor prin injectarea dimetoatului în tulpinile arborilor [Stem injection of dimethoate for control of European larch (Larix decidua Mill.) cone and seed insects]

The systemic insecticide dimethoate (0.20 g active ingredient and 0.30 g active ingredient per cm dbh, in 1990 and 1991 respectively) was injected into European larch trees to determine its effectiveness in controlling cone and seed insects. Percentages of cones and seeds damaged by insects and germination of seeds were assessed. The treatments were more effective against the larvae of Strobilomyia spp. and Retinia perangustana, and less effective against those of Resseliella skuhravyorum. The percentages of seeds damaged by the above mentioned pests were diminished by 47-94 %, 37-83 % and 30-39 % respectively. In addition, the treatments increased the percentage of filled seeds, and consequently the overall effectiveness was of 55.2 % in 1990, and 86.6 % in 1991. They did not reduce the percentage of germinated seeds. The best results have been obtained when the treatment was conducted earlier, that means at the beginning of R. skuhravyorum eggs hatching. Therefore, we reccomend the treatment to be done just prior to female bud flush

Cephalcia abietis (L.) (Hymenoptera: Pamphiliidae) - un nou dăunător al pădurilor de molid din România [ Cephalcia abietis (L.) (Hymenoptera: Pamphiliidae) - a new pest of the Norway spruce forests in Romania]

. Defoliation of some Norway spruce stands, caused by Cephalcia abietis, was first reported in Romania in the autumn of 2015. The outbreak has affected 58 ha in the Eastern Carpathians and 190 ha in the Southern Carpathians. The species was previously known only as a faunistic element in the country and very little information on its biology, ecology, detection, forecast and population control is available in the Romanian literature. This paper is a synthesis of information concerning the web-spinning spruce sawfly, whose aim is to fill the knowledge gap. C. abietis is a species with a vast distribution area, but repeated outbreaks were reported especially from Central Europe. In the outbreak areas, the most insects of a generation need 2-3 years to complete their development, so that an intense flight and a stronger defoliation take place every 2-3 years. Although mortality factors affecting the populations of C. abietis are very numerous, they fail to keep defoliator populations under control and outbreaks may extend for a long time. Mass multiplication occurs mainly in pure Norway spruce stands older than 60 years, at medium altitudes (600-1000 m), in places exposed to periodic drought or pollution. Biological and ecological peculiarities of this species make the prognosis of defoliation much more labor intensive than that for other defoliators, although quite uncertain. The chemical control, with partially selective insecticides (chitin synthesis inhibitors), was usual during recent decades, while biological control is still in the experimental phase. Consequently, greater emphasis should be placed on preventing mass multiplication of this specie

Noi semnalări ale unor specii de insecte forestiere invazive în România [ New records of some invasive forest insect species in Romania]

New records of ten invasive insect species in Romania are presented. The studied species are: Cameraria ohridella Deschka & Dimic 1986, Parectopa robiniella Clemens 1863, Phyllonorycter robiniella (Clemens 1859), Phyllonorycter issikii (Kumata 1963), Hyphantria cunea (Drury 1773), Obolodiplosis robiniae (Haldeman 1847), Leptoglossus occidentalis Heidemann 1910, Eopineus strobus (Hartig 1837), Megastigmus spermotrophus Wachtl 1893 and Harmonia axyridis Pallas 1773. The native range of each species, the first report and the present distribution in Europe and in Romania are discussed. The new records suggest that all the analysed species have established populations in our country and a more widespread distribution than that previously known. Some of them attain sometimes locally or zonally high population levels and are regarded as important pests. For the most species, new observations are necessary, both concerning their presence in the areas where they were not found so far, but also to assess the impact of insect populations on their hosts and on the recipient biocoenoses. A particular attention should be paid to the species H. axyridis, whose swarms invade the houses of the people during the autumn and could cause annoyance and possibly allergy. Citizen participation in observing and reporting of these new ”guests” is encouraged