The leopard moth borer, Zeuzera pyrina L., is a cossid moth whose larvae bore into twigs, branches and trunks of various woody species, weakening and sometimes killing trees or shrubs. Recently it caused serious losses of apple trees in Bulgaria. In a three-year-old non-protected apple orchard in the Plovdiv region more than 30% of trees perished due to damage by this pest. In the nursery and in commercial orchards up to 5% of branches were injured. Main damage was observed in August and September. Both cossids, Zeuzera pyrina and Cossus cossus, damaged 15–20% of the stems in old commercial orchards and more than 60–70% in orchards without regular plant protection. In this study flight dynamics of Z. pyrina was monitored by two types of pheromone traps: Pherocon (Trécé, USA) – traps with sticky changeable bottom and Mastrap (Isagro, Italy) – dry funnel traps. The second type was more effective. Flight of moths lasted from mid-June to the beginning of September. Pheromone traps may be helpful in IPM systems, for signalling optimal time for spraying against this pest. Further studies are needed to determine correlation between the catches in pheromone traps and appearance of injuries.
This paper presents a preliminary report of Fusarium wilt of Roselle in the Nigerian savanna. Soil and plant samples were collected from eight experimental plots where plants showed Roselle wilt symptoms. Samples were analyzed for the presence of nematodes and wilt pathogens. The wilt causative organism Fusarium oxysporum was isolated together with nematodes of different genera. However, nematodes of the genus Helicotylenchus, Scutellonema and Hoplolaimus appeared to occur in higher densities than the others.
The resistance of winter wheat varieties to Puccinia recondite f. sp. tritici was investigated at the Lithuanian Institute of Agriculture during 2001–2003. Effectiveness of resistance genes was investigated at seedling, tillering and adult plant stages. Virulence tests done during the 2000–2003 period showed that the majority of Lr genes used in European wheat were not sufficiently efficient. However, testing of cultivars at the first leaf stage revealed that the Lr37 gene in combination with the other genes was very effective. The experimental cultivars were sown in 2 times: in autumn and spring, without vernalization. The main task of spring-sown nursery was to improve the effectiveness of the experiment and investigate the effect of different Lr genes of non-vernalized plants at tillering growth stage. The Lr37 gene was found to be the most effective at both adult plant stage and tillering growth stage. Disease severity and plant resistance type at tillering stage were stable in all experimental years, which is important for the breeding program. The investigations revealed that the correlations between resistance at seedling and the other two stages were up to r = 0.81 (significant at p = 0.01**). The correlations between leaf rust severity and varietal resistance type at tillering were very high (r = 0.86–0.91**) in the same year. The correlation of leaf rust severity at adult plant stage was strong (r = 0.78**) between 2001 and 2002, but too low for reliable selection of resistant cultivars in the other years. Spring-sown nursery was complementary to collect resistance data in the years unfavourable for leaf rust development.
Trinexapac-ethyl is one of the newest growth regulators used in agriculture and horticulture. As a most growth retardants it acts by inhibiting gibberellin (GA) biosynthesis. A field study was conducted to determine the effects of trinexapac-ethyl on growth of winter wheat. Trinexapac ethyl was used alone (75 g a.i./ha and 125 g a.i./ha) and in the mixture with chlorocholine chloride (50 g a.i./ha + 675 g a.i./ha) at the 2nd node stage. Trinexapac-ethyl and its mixture with CCC activity was weather dependent. Their influence on the crop was strictly related to the temperature and rainfall during an individual year of trials. Plant growth regulators much more influenced winter wheat plants in abundant rainfall and higher temperature conditions. Lodging was not observed during the experiment.
Analyses of the ground waters in respect of presence of residues of plant protection products, i.e. active substances as well as environmental metabolites thereof are performed in the Institute of Plant Protection since the end of 80ties of the past Century. Based on the results obtained in 1993–1994 for 40 wells located in administrative territories of former Poznań, Toruń and Bydgoszcz voivodeships, in the vicinity of intensive agricultural production areas (orchards, farms), wells where significant amounts of residues of triazines group and dealkylated metabolites thereof had been found previously were qualified to further studies. There were 6 wells in which triazine residues were determined most often. Additionally, based on hydrogeological maps, directions of underflows in the areas of well’s locations were determined as well. The aim of the above was to find the additional places for sampling waters distant from pollution sources and estimation of the level of residues of target compounds depending on distance from the basic wells. Seven triazine compounds including basic active substances (atrazine, simazine) and their metabolites [desethyl atrazine, desisopropyl atrazine, desethyldesisopropyl atrazine, hydroxyatrazine and hydroxysimazine] were selected for the presented studies. Residues were analyzed using methodologies designed in the Institute, i.e. solid-phase extraction (SPE) followed by determination by chromatographic techniques HPLC-PDA, GC-NPD and GC-MS. Generally, during 11 years of investigations (1993–2003) samplings were performed 52 times and 323 samples of groundwater including that from additional wells were analyzed. Most often residues of atrazine and deethylatrazine in wells located in environs of Poznań were detected.
In this paper we present the first occurrence of the Diabrotica virgifera Le Conte in Poland and the measures taken against this pest. The specimens of western corn rootworm were found in South-Eastern Poland (Podkarpackie voivodeship) at the end of August and in September of 2005.
Phytophthora citricola Sawada was detected from 3 water pools situated in 2 container- grown nurseries. The highest number of spots on rhododendron leaves were observed in June whereas the lowest in October. The use of water for plant sprinkling caused browning, yellowing of shoots and root rot of Buxus sempervirens, and blight of shoot tips of Thuja occidentalis and Rhododendron sp. The disease symptoms were observed already in June and the disease developed till the first decade of October. Losses caused by the species varied from 9 to 56%.
The bionomy and ecology of Amphorophora idaei (Bőrn.) on raspberry was studied under insectary conditions and in two rasberry farm plantations in 1997–2002. In 2001 and 2002 the development and fecundity of A. idaei under controlled conditions were also observed.
In 1993–1997 the occurrence of Lepidoptera pests: Pieris rapae L., Pieris brassicae L., Mamestra brassicae L., and Plusia gamma L. were observed on the nine different late cabbage vegetables; Savoy cabbage cv. Vertus, white cabbage cv. Amager, red cabbage cv. Langendijker, brussel sprouts cv. Maczuga, cauliflower cv. Pionier, blue kohlrabi cv. Masłowa, white kohlrabi cv. Delikates, kale cv. Zielony Kędzierzawy and broccoli cv. Piast. The field observations showed that butterflies differentiated among host-species for oviposition. The butterfly females of all species preferred for oviposition the brussel sprouts and deposited a substantially larger number of eggs on leav es of them. Plant species with green leaves were more preferred than the red leaf ones.
One of the negative aspects of the intensive use of herbicides is related to the selection of resistant biotypes (Gasquez 2001). Of all biotypes resistant to herbicides, 93 species do not respond to sulfonylurea herbicides (ALS-inhibiting herbicides). The acetolactate synthase (ALS) enzyme is the first step in biosynthesis of a branched chain amino acids (valine, leucine, isoleucine). In Poland the problem of resistance to sulfonylurea herbicides has been discussed since 2001 (Rola and Marczewska 2002). Resistance tests of Apera spica-venti biotypes were conducted in the greenhouse conditions. Chlorsulfuron was applied at the four-leaf stage of development at rates ranging from 11.25 to 360 g/ha. In confirmation of resistance to chlorsulfuron as identified in biological tests, the chemical analyses were performed. The analyses investigated the influence of different doses of chlorsulfuron on free amino acids content in the aboveground part of resistant and susceptible Apera spica-venti. The analyses were carried out applying high performance liquid chromatography method (HPLC). The resistance of the biotype was confirmed in amino acids analysis. In the resistant biotype followed the increase of valine, leucine and isoleucine concentration in comparison with untreated plants and those susceptible to chlorsulfuron biotype.
The paper reports results of investigations concerning the influence of saponin extract of quillaja on the food choice and development of Colorado potato beetle. Choice tests with the use of potato leaf discs treated and untreated with tested saponins’ extract were made. The influence of the presence of saponins on the food choice and intensity of insect feeding were observed. It was stated that saponins significantly restrain feeding and disturb development of this pest.