The aim of the study carried out during 2002–2004 was to assess the effects and economic effectiveness of application of fungicides and insecticides in winter triticale crops. Its leaves were attacked by pathogenic fungi in 43.2% to 52.2% and the damage to leaf blade surfaces by cereal leaf beetle (Oulema spp.) ranged from 23.6% to 34.4%. The effectiveness of applied fungicides ranged from 44.7% to 90.8%, and that of insecticides was within 70.1% and 94.4%. The saved crops were evaluated for PLN 198 to 1 171 per ha. The cost coverage ratio ranged from 0.7 to 9.9 and the treatment profitability index ranged from 0.9 to 7.4. Cost index in percentage ranged from 0.8 to 8.5, with its average value of 4.2.

The efficacy of solar heat in the control of bacterial soft rot of potato tubers was investigated in Maiduguri, semi-arid region of Northeastern Nigeria. Artificially contaminated tubers were exposed to solar heat for duration of 0, 30, 60, 120 and 180 minutes. The results showed that exposures for 120 and 180 minutes gave the highest control of the disease, although during the hot dry season (mean temperature at exposure was 54.6°C) exposure even for 30 minutes gave satisfactory control of the disease. Solar heat can therefore be used to control of bacterial soft rot of potato tubers.

In order to assess the economic benefits of reduced fungicide application for the control of paprika diseases under dryland conditions, on-farm experiments were conducted in the Chinyika Resettlement Area in the Eastern province of Zimbabwe in the 2000/2001 and 2001/2002 seasons. The six fungicide application regimes that were assessed include: weekly interval sprays; Sulphur at 2 weeks after transplanting (WAT) and copper oxychloride-Mancozeb mixture at 6 WAT; spraying after scouting; alternating Sulphur and copper oxychloride- Mancozeb every two weeks; Acibenzolar-s-methyl and unsprayed check. Parameters recorded were disease severity and yield; after harvest an economic analysis was performed. The highest added profit of Z$ 75 930/ha was recorded in the weekly sprayed plots which was not statistically different (p > 0.05) from Z$ 59 410/ha achieved by alternating copper oxychloride and Mancozeb fortnightly at Dengedza site in 2000/2001 season. There were no statistical differences (p > 0.05) between spraying after scouting and Acibenzolar-s-methyl application treatments as they added the least profits of Z$ 990/ha and Z$ 17 250/ha respectively at the same site in the same season. These have serious implications for smallholder farmers in terms of cost savings. Neither were there differences (p > 0.05) in added profits from different spraying regimes at Dengedza site in the 2001/2002 rainy season.

Phytophthora root and stem rot of soybean is a destructive disease of soybean in Iran. During 1998–2005, 142 isolates from soil and diseased soybean plants were collected and tested. Race identification was made possible by inoculating Rps differential soybean cultivars and lines. Of the 142 isolates tested, 110 isolates belonged to race 1 and 32 isolates belonged to race 3. Race 1 was domi nant in soil and diseased plant samples. There was no variability in virulence of Phytophthora sojae between the areas surveyed.

An evaluation of the effect of four host plants on biological parameters of Maconellicoccus hirsutus and efficacy of Anagyrus kamali was conducted in the laboratory. Hibiscus rosa-sinensis and Hibiscus sabdariffa produced M. hirsutus with life cycles which were 1–2 days shorter than those of M. hirsutus reared on Solanum tuberosum, and Cucurbita pepo L. Egg to adult M. hirsutus survival was lowest in C. pepo (8.8%) and highest for H. sabdariffa (21.8%). C. pepo, H. rosa-sinensis and H. sabdariffa produced a more female biased M. hirsutus sex ratio from single ovisacs, than S. tuberosum. Although adult M. hirsutus females exhibited variation in size and longevity on the host plants tested, total fecundity was not significantly different. Life cycle of both sexes and offspring sex ratio of A. kamali emerging from M. hirsutus cultured on the four host plants were statistically similar. M. hirsutus infested H. rosa-sinensis and H. sabdariffa produced A. kamali with significantly higher fecundity (post emergence adult counts) and lower longevity compared to the other host plants. Females with largest femur (Mean length = 0.2950 ± 0.0053 mm) were produced by M. hirsutus infested H. rosa-sinensis. A. kamali efficacy measured by percent parasitization and percent adult eclosion was statistically similar for all M. hirsutus infested host plants tested.

The tomato yellow leaf curl virus infecting tomato plants in Tanzania is reported to be different from the Old World geminiviruses. A study was initiated to investigate the transmission properties of the virus such as, acquisition feeding time, inoculation feeding time, persistence of virus in the vector, mechanical inoculation, seed and graft transmission. Results obtained indicate that the virus is transmitted persistently by Bemisia tabaci Genn., but neither mechanically – nor seed-transmissible. Minimum acquisition and inoculation time was 30 minutes. It is concluded that the properties of the agent causing the yellow leaf curl symptoms in tomato plants from different regions of Tanzania are similar and mimic those of tomato yellow leaf curl Begomovirus species studied elsewhere.

Observations on the incidence, harmfulness and some elements of Cameraria ohridella control on white horse chestnut (Aesculus hippocastanum L.) were carried out in Wrocław, Poland, in 2001–2003. Three generations of the pest developed on A. hippocastanum. The leaf infestation by pest’s larvae increased systematically throughout the spring-summer season. Cultural control by removing the fallen leaves was suggested. Using this procedure, the abundance of the pest was considerably reduced, therefore, the percentage of the leaf damage was lower and the trees lost these leaves later in the season.

In the four-year experiment the impact of four different winter barley varieties and selected two- and three-component mixtures were tested. Reduced dosages of fungicides on disease reduction in the mixtures compared with pure stands were evaluated. The studies were carried out at two sites: Experimental Station for Variety Testing Słupia Wlk. (Wielkopolska region) and Plant Breeding Station Bąków (Opole District). Observations on powdery mildew occurrence during the vegetation season were done every 7–10 days. In order to compare the disease occurrence levels on different cultivars in pure stands and on their mixtures combined with different fungicide treatments the Area Under Disease Progress Curve (AUDPC) was evaluated. On the base of the AUDPC values the reduction of powdery mildew occurring in the mixtures due to epidemiological and ecological factors functioning in mixed stands were also evaluated. On the base of obtained results it can be stated that winter barley variety mixtures combined with different fungicide treatments do reduce the powdery mildew incidence comparing to pure stands and winter barley variety mixtures can constitute an alternative way of growing winter barley, especially at low-input and ecological agriculture.

In the four-year experiment the impact of four different barley varieties and selected two-and three-component mixtures were tested. The studies were carried out at two sites: Experimental Station for Variety Testing Słupia Wlk. (Wielkopolska region) and Plant Breeding Station Bąków (Opole District) during four growing seasons (2001/2002–2004/2005). The aim of the studies was to evaluate the yield through growing barley variety mixtures in combination with reduced use of fungicide and application dose rates. Positive effects (1–15% yield increase in mixtures compared to pure stands) were observed. On the base of obtained results it can be stated that winter barley variety mixtures can constitute an alternative way of growing winter barley, especially at low-input and ecological agriculture.

Observations were carried out in apple orchards and nurseries of the Plovdiv region (Central-South Bulgaria), aimed at determining specific composition, population density and economic importance of particular species of aphids, in the years 2004–2006. By surveys, carried out at 15-day intervals, the appearing species were identified and the degree of damage determined. Six species of aphids were found: Aphis spiraecola Patch., A. pomi Deg., Dysaphis plantaginea Pass., D. devecta Wlk. Rhopalosiphum insertum Wlk. and Eriosoma lanigerum Hsm. A. spiraecola, a poliphagous pest, was probably brought with the plant material from Greece and was identified in Bulgaria for the first time. It is similar to A. pomi and may be distinguished only by the microscopic investigation. Aphis spiraecola replaced almost completely A. pomi in the region studied. Its population was particularly high in nurseries. In the bearing orchards D. plantaginea was the most important aphid. Some tendency to an increase of population and damage caused by D. devecta was also noted. The other species had not any economic importance. E. lanigerum was present only in the orchards where no chemical control was applied.