The occurrence of Megastigmus pictus (Förster) (Hymenoptera: Torymidae) and Resseliella skuhravyorum Skrzypcz. (Diptera: Cecidomyiidae) in the Chełmowa Góra forest reserve of theŚwiętokrzyskiNational Park (Poland)
A study conducted in 1999–2000 in 6 compartments of the Chełmowa Góra forest reserve, situated in the ŚwiętokrzyskieMountains, was aimed at harmful insects infesting cones and seeds of Larix decidua Mill. subsp. polonica (Racib.) Domin. Insect rearing and seed and cone cutting yielded 1,045 specimens of insects belonging to <br />8 species. Resseliella skuhravyorum Skrzypcz. (Diptera: Cecidomyiidae) and Megastigmus pictus (Förster) (Hymeno-ptera: Torymidae) were the most abundantly represented species. They were present in cone samples of all investigated trees. The index of infestation of cones by insects (WZS) was higher in the case of trees growing at the forest edge. The analysis by cutting showed an insignificant percent increase – 6.7% of sound seeds while 88.9% of seeds were blind. M. pictus damaged 2.6% of larch seeds, while R. skuhravyorum 1.7%. The parasitoid Mesopolobus zetterstedtii (Dalla Tore) was received from the mass rearing where its host is M. pictus.