Systemic release of herbivore-induced plant volatiles by turnips infested by concealed root-feeding larvae Delia radicum L.

When attacked by herbivorous insects, many plants emit volatile compounds that are used as cues by predators and parasitoids foraging for prey or hosts. While such interactions have been demonstrated in several host-plant complexes, in most studies, the herbivores involved are leaf-feeding arthropods. We studied the long-range plant volatiles involved in host location in a system based on a very different interaction since the herbivore is a fly whose larvae feed on the roots of cole plants in the cabbage root fly, Delia radicum L.

Selectivity assessment of chlorfenvinphos reevaluated by including physiological and behavioral effects on an important beneficial insect.

Selectivity is an important factor in identifying candidate pesticides to be used in crop protection since it characterizes chemicals that, while being effective against target pests, exert an acceptable impact on the other components of the environment. Extrapolated to an integrated pest management (IPM) context, selectivity implies that candidate pesticides may preserve the ability of beneficial insects to significantly control target pest populations. In the present study, we assess the physiological selectivity of the organophosphate chlorfenvinphos, used to protect cruciferous crops against the cabbage root fly, Delia radicum (Diptera: Anthomyiidae), by investigating both the lethal and sublethal effects exerted on its main parasitoid Trybliographa rapae (Hymenoptera: Figitidae).

Measurement of insecticide uptake and effective fraction in a beneficial insect using solid-phase microextraction.

The determination of insecticide uptake in beneficial insects is important for quantifying the doses that are responsible for the toxicological effects and to compare them with the doses that insects may absorb in treated fields. Because of the small size of some beneficial species, the amount of insecticide absorbed may be very low. Herein, we present a method that relies on the sensitivity and specificity of SPME (solid-phase microextraction) as a sampling technique that can be used to measure very small amounts of an organophosphorus insecticide in small insects.

Geographical origin of an introduced pest species, Delia radicum (Diptera: anthomyiidae), determined by RAPD analysis and egg micromorphology.

The origin of introduction of the cabbage root fly, Delia radicum Linnaeus to the north-eastern coast of North America in the 19th century has been assumed to be from Europe. From that point of introduction, D. radicum gradually spread westward to occupy available ecological niches.

[Micro-morphology of the ovipositor in Hymenoptera and evolution from phytophagous Symphyta to parasitoid Apocrita].

The ovipositor of 1 Symphyta and 12 primitive parasitoid Apocrita belonging of the family of Ichneumonidae has been studied with the scanning electron microscope (SEM) and for 2 species, semi-thin sections were used. The study shows the presence of closed trachea in the 3 pairs of valvulae and a secretory system in the 2 pairs of valvulae interlocked into a piercing stylus. We discuss the role of trachea and a secretory system leading to excretory pores on the lancets of valvulae which occupy very precisely the site of sensory chemoreceptors known in more advanced species lacking this secretory system.