The insecticidal efficacy of Gmelina arborea L. product extracts was assayed for suitability in controlling the legume pod borer Maruca vitrata Fab. (Lepidoptera: Pyralidae) and the pod sucking bug Clavigralla tomentosicollis Stäl (Hemiptera: Coreidae) on cowpea. Field studies conducted in 1999 and 2000 cropping seasons at the research farm of the Institute for Agricultural Research, Samaru showed that extract of Gmelina arborea fruit at 10% (w/v) caused impressive reduction ofboth pests and protected the pods from serious damage. Grain yield was higher in the fruit extract treated plants compared to the leaf, bark treatments and the untreated control. However, all the Gmelina products’ extracts were superior (p < 0.05) to the untreated control but was not better than the synthetic insecticide (Sherpa Plus) used in all the assessments made. This study is the first reported case ofthe potential of Gmelina arborea products’ extracts for control of Maruca pod borer larvae and pod sucking bug on field cowpea. This plant could add to the pool of herbal landraces already found to be insecticidal to insect pests of tropical crops if explored and exploited for use by limited resource farmers in tropical countries.
In1993–1997 the occurrence of predatory syrphids inthe cabbage aphid (Brevicoryne brassicae L.) colonies was observed on the nine different cabbage vegetables: savoy cabbage cv. Vertus, white cabbage cv. Amager, red cabbage cv. Langendijker, brussels sprout cv. Maczuga, cauliflower cv. Pionier, blue kohlrabi cv. Masłowa, white kohlrabi cv. Delikates, kale cv. Zielony Kędzierzawy and broccoli cv. Piast. The number of aphids as well as amount of aphidophagous Syrphidae feeding in their colonies on the different cabbage vegetables were compared. The species compositionwas also estimated. Eight species of Syrphidae were collected: Episyrphus balteatus (Deg.), Sphaerophoria scripta (L.), S. rueppelli (Wied.) S. menthastri (L.), Metasyrphus corollae (Fabr.), Scaeva pyrastri (L.), Syrphus vitripennis (Meig.), Paragus quadrifasciatus (Meig.). In the all years of observation the dominant species were E. balteatus (Deg.), S. scripta (L.) and S. rueppelli (Wied.). The highest number of syrphid larvae were collected from cabbage aphid colonies on the white and savoy cabbage.
The subject of the performed experiments comprised standard RSMM 110-02, RSMM 110-02 nozzles, AI 110-02, AI 110-02 air induction nozzles as well as AZMM 110-02, AZMM 110-03 low drift nozzles. The working speed during spraying was vp = 7 km/h. Each sprayer was tested at the following three levels of working pressures: p1 = 0.2 MPa, p2 = 0.4 MPa and p3 = 0.6 MPa. The spray liquid was pure water at the temperature of 20°C. The plant coverage was determined: sk – spray coverage, nk – number of droplets per 1 cm2 of the leaf.
The incidence of fusarium foot-rot occurrence on the winter wheat cultivars Roma and Sakwa was examined in the years 2001–2003. Strict plot experiments were set up by the method of random sub-blocks in Tomaszkowo near Olsztyn. Fungicides were applied on the growing plants during the periods of shooting and heading. The control plots were sprayed with water. The sanitary state of leaf sheaths was evaluated at heading phase (GS 55). The symptoms of fusarium foot-rot were examined at the phase of milky maturity (GS 75) and waxy maturity of grain (GS 87). The study aimed at assessing the average index of infection of the winter wheat stem base caused by the species of Fusarium genus, assessing the vulnerability of the Roma and Sakwa cultivars to these fungi and determining the effectiveness of pesticides in control of fusarium foot-rot. Fusarium foot-rot (Fusarium spp.) of winter wheat dominated on the winter wheat stem base. Most of the examined stems were severely infected. The Roma cultivar was more susceptible to infection by Fusarium fungi than the Sakwa cultivar. The effectiveness of fungicides in controlling fusarium foot-rot on the winter wheat was satisfactory, but largely depended on the cultivar and weather conditions. Mirage 450EC and Sportak Alpha 380EC fungicides were the most effective. The species F. culmorum and F. avenaceum dominated in the fungal populations colonizing the stem base of winter wheat with visible symptoms typical of fusarium foot-rot.
The incidence of winter wheat stem base diseases: Fusarium foot rot (Fusarium spp.), eyespot (Ramulispora herpotrichoides), sharp eyespot (Rhizoctonia spp.) and take-all (Gaeumannomyces graminis) in the years 1999–2003 was assessed in this study. Previous crops were barley and oilseed rape. Eyespot occurred on the greatest percentage of plants throughout the whole period of the study. In 2000–2003 a deficiency of rainfall was observed, especially at the time of increased water requirements of plants.
The trials conducted with selected chemical and biological insecticides in 1998-2000 showed the highest effectiveness of Karate Zeon 100 CS (lambda-cyhalotrine) in European corn borer (ECB) larvae control in sweet corn. The efficacy of biological insecticides containing Bacillus thuringiensis ssp. kurstaki: Biobit 3.2 WP and Lepinox WDG was very variable between the years. Reasons for insufficient efficacy of these products are discussed. The most appropriate time for the application of a chemical insecticide against ECB larvae are plant developmental stages since the beginning of pollen shedding to full blooming (63–67 BBCH scale). The efficacy of treatment was the highest at that time.
The kairomone, ethyl (2E,4Z)-2,4-decadienoate, a potent attractant of both males and females of Cydia pomonella in regions of the USA, was tested alone and together with the synthetic sex pheromone in apple orchards of Bulgaria in 2002 and 2003. No female moths were caught in any trap containing kairomone as a lure or lure component. Furthermore, traps baited with kairomone caught only low numbers of males. Greatest numbers of male moths were caught in traps baited with the “combined-lure,” comprised of pheromone and kairomone together.