Melolontha grubs are polyphagous and are adapted to feeding on plants of varying nutritional value. Our research sought to investigate whether host plant quality affects first-instar grub development, weight gain, or mortality. Ten plant taxa of the families Polygonaceae, Brassicaceae, Asteraceae, Fabaceae, and Pinaceae were tested. The quality of each plant species was estimated based on the root content of phenols, condensed tannins, soluble sugars, starch, nitrogen, and carbon. Retarded development, high mortality, and low weight gain were observed in grubs feeding on roots of Fagopyrum esculentum, Brassica rapa subsp. rapifera, and B. napus, whereas Tanacetum vulgare, Trifolium repens, and Lupinus polyphyllus roots proved to be the most beneficial for larval performance. Weight gain was positively correlated with the concentration of soluble sugars and starch in the plant roots. Starch was also positively correlated with the percentage of molted grubs. The revealed positive correlations may be explained by the fact that nonstructural sugars constitute an energy source that is essential for grub movement in the soil. Plant species that negatively affect cockchafer grubs may be used in integrated plant protection against these pests in agriculture, horticulture, and, to some extent, in forestry, e.g., in nurseries and postagricultural lands.
Data is given on occurrence of Lymantria dispar in Poland, and on infested forest areas, over the period 1945/1994. Outbreaks occurred in 1952/1956, 1966/1971, 1980/1986 and 1992/1994, which corresponded with other outbreaks of this pest in Central Europe. A breeding area of L. dispar has been recognized in marshes and forests in north‐eastern Poland, adjoining Belarus. Information is also provided on the pest status of six other Lymantriidae: Dasychira pudibunda, Euproctis chrysorrhoea, E. similis, Leucoma salicis, Lymantria monacha and Orgyia antiqua. A list of pathogens and parasitoids recorded in larvae and pupae of L. dispar in Poland is given.
This study estimates the efficacy of an attract-and-kill (A&K) technique to control the horse chestnut leaf miner, Cameraria ohridella Deschka and Dimic (Lepidoptera, Gracillariidae), an invasive insect pest of the horse chestnut, Aesculus hippocastanum L. (Hippocastanaceae). The A&K formulation was dispensed as 50 μl droplets of paste-like matrix, containing C. ohridella sex pheromone, (8E,10Z)-tetradeca-8,10-dienal (85% + pure; 0.16% w/w) and a fast acting contact toxicant, pyrocides (94% pure; 6% w/w), applied directly to the bark of the trees. It was tested in 2003 at rates of 30 and 45 droplets/tree at the Ostrobramska site and at rates of 30, 60 and 90 droplets/tree at the Woloska site in Warsaw, Poland, for the first insect generation. A set of untreated plots (0 droplets/tree) was established at each site as well. The treatment efficacy was estimated using two indices: (1) moth catches in pheromone traps and (2) the number of mines per leaf. Trap catches were significantly higher in the untreated plots than in the treated plots regardless of the application rate in all sites. However, there were no significant differences in leaf damage amongst all plots on each site. At the “Lazienki Krolewskie” park the attractiveness of two types of pheromone sources were compared: traps were baited with rubber septum lures or with A&K droplets. The catches of C. ohridella in traps baited with lures were lower than captures in A&K droplet-baited traps, but the difference was not significant. Possible reasons for the low efficacy of the A&K method in management of C. ohridella and reducing leaf damage are discussed.
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