Phenolic and lipophilic compounds of wheat grain as factors affecting susceptibility to infestation by granary weevil (Sitophilus granarius L.)

The impact of certain groups of polyphenolic (phenolic acids and alkylresorcinols) and lipophilic compounds (total lipids, fatty acids, sterols, tocols and carotenoids) on susceptibility of bread wheat (Triticum aestivum L.) kernels to Sitophilus granarius infestation was studied. In the experiments, six cultivars of spring wheat with comparable protein content, endosperm hardness and overall technological quality were used. Twenty grams of grain were infested by 10 pairs of beetles and stored for one week or eight weeks at 28±2°C and relative humidity of 60%. The intensity of growth and feeding of S. granarius varied significantly in the used cultivars. The antixenosis effect of the studied grain chemicals, observed after one week of infestation, was the lowest for Łagwa cv., which was characterized by the highest total lipid and sterol contents. Other cultivars showed a similar antixenosis effect. For antibiosis effect, the most attractive for S. granarius infestation was Ostka Smolicka cv., which was characterized by the lowest content of total phenolic acids. In contrast, the highest antibiosis effect was found for Arabella and Izera cvs. with the lowest values of sterol content and average values of other determined phytochemicals

The cultivation of phacelia (phacelia tanacetifolia benth.) as a habitat for the occurrence of beneficial ground beetles (coleoptera, carabidae)

Badania dotyczyły poznania zgrupowań biegaczowatych (Col. Carabidae), występujących w uprawie facelii błękitnej. Badania prowadzono w latach 2008–2009 w Bartążku koło Olsztyna. Biegaczowate były odławiane do pułapek Barbera od maja do końca września każdego roku. Ogółem odłowiono 2425 osobników należących do 37 gatunków. Zaobserwowano wysokie wartości wskaźników różnorodności gatunkowej biegaczowatych występujących w uprawie facelii. Stwierdzono występowanie biegaczowatych, należących do różnych grup ekologicznych, szczególnie dużych zoofagów mogących mieć wpływ na ograniczanie liczebności szkodników roślin. Uprawy facelii błękitnej stanowią element infrastruktury ekologicznej w agrocenozach, stwarzającej warunki sprzyjające występowaniu drapieżców.The research concerned the knowledge of carabid beetles (Col. Carabidae) assemblages, occurring in the cultivation of tansy phacelia. The study was conducted in 2008–2009 in Bartążek near Olsztyn. Ground beetles were caught into Barber traps from May to September each year. In total, 2,425 individuals belonging to 37 species were captured. It was observed high values of species diversity of beetles occurring in the phacelia crop. There were a lot of valuable species of ground beetles, belonging to different ecological groups, especially large zoophages which may have an impact on reducing the number of plant pests. It was found that the cultivation of phacelia may be a valuable element of ecological infrastructure in agrocenosis creating conditions conducive to the presence of predators

Effect of Soy Leaf Flavonoids on Pea Aphid Probing Behavior

Flavonoids detected in soybean Glycine max (L.) Merr. (Fabaceae) cause various alterations in the metabolism, behavior, and development of insect herbivores. The pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) poses potential threat to soybeans, but the effect of individual flavonoids on its feeding-associated behavior is relatively unknown. We monitored probing behavior (stylet penetration activities) of A. pisum on its preferred host plant, Pisum sativum L. untreated (control) and treated with 0.1% ethanolic solutions of flavonoids apigenin, daidzein, genistein, and kaempferol. We applied the electrical penetration graph (electropenetrography, EPG) technique, which visualizes the movements of aphid stylets within plant tissues. None of the applied flavonoids affected the propensity to probe the plants by A. pisum. However, apigenin enhanced the duration of probes in non-phloem tissues, which caused an increase in the frequency and duration of stylet mechanics derailment and xylem sap ingestion but limited the ingestion of phloem sap. Daidzein caused a delay in reaching phloem vessels and limited sap ingestion. Kaempferol caused a reduction in the frequency and duration of the phloem phase. Genistein did not affect aphid probing behavior. Our findings provide information for selective breeding programs of resistant plant cultivars to A. pisum

Quercetin and Rutin as Modifiers of Aphid Probing Behavior

Rutin and its aglycone quercetin occur in the fruits, leaves, seeds, and grains of many plant species and are involved in plant herbivore interactions. We studied the effect of the exogenous application of rutin and quercetin on the probing behavior (= stylet penetration activities in plant tissues) of Acyrthosiphon pisum on Pisum sativum, Myzus persicae on Brassica rapa ssp. pekinensis, and Rhopalosiphum padi on Avena sativa using the electrical penetration graph technique (EPG = electropenetrography). The reaction of aphids to quercetin and rutin and the potency of the effect depended on aphid species, the flavonol, and flavonol concentration. Quercetin promoted probing activities of A. pisum within non-phloem and phloem tissues, which was demonstrated in the longer duration of probes and a trend toward longer duration of sap ingestion, respectively. M. persicae reached phloem in a shorter time on quercetin-treated B. rapa than on the control. Rutin caused a delay in reaching sieve elements by A. pisum and deterred probing activities of M. persicae within non-phloem tissues. Probing of R. padi was not affected by quercetin or rutin. The potency of behavioral effects increased as the applied concentrations of flavonols increased. The prospects of using quercetin and rutin in plant protection are discussed