Effect of petroleum-derived substances on life history traits of black bean aphid (Aphis fabae Scop.) and on the growth and chemical composition of broad bean.

The aim of the study was to determine the effects of various petroleum-derived substances, namely petrol, diesel fuel and spent engine oil, on life history traits and population dynamics of the black bean aphid Aphis fabae Scop. and on growth and chemical composition of its host plant Vicia faba L. Each substance was tested separately, using two concentrations (9 g kg and 18 g kg). The experiment was conducted in four replications (four pots with five plants in each pot per treatment). Plants were cultivated in both control and contaminated soils. After six weeks from soil contamination and five weeks from sowing the seeds, observations of the effect of petroleum-derived substances on traits of three successive generations of aphids were conducted. Aphids were inoculated separately on leaves using cylindrical cages hermetically closed on both sides. Contamination of aphid occurred through its host plant. Results showed that all tested substances adversely affected A. fabae life history traits and population dynamics: extension of the prereproductive period, reduction of fecundity and life span, reduction of the population intrinsic growth rate. In broad bean, leaf, roots, and shoot growth was also impaired in most conditions, whereas nutrient and heavy metal content varied according to substances, their concentration, as well as plant part analysed. Results indicate that soil contamination with petroleum-derived substances entails far-reaching changes not only in organisms directly exposed to these pollutants (plants), but also indirectly in herbivores (aphids) and consequently provides information about potential negative effects on further links of the food chain, i.e., for predators and parasitoids.