Comparing an IPM pilot program to a traditional cover spray program in commercial landscapes

An integrated pest management (IPM) pilot program for landscape plants was implemented during 1997 and 1998 on two commercial, two residential, and one institutional property managed by landscape professionals. When compared with preprogram, calendar-based cover spray program costs at these sites in 1996, the IPM program was cost-effective at one of the five sites in both 1997 and 1998, and cost effective at a second additional site in 1998 when the cooperator, initially skeptical of IPM, discontinued calendar-based cover sprays performed in 1996 and 1997. The mean cost per site was $703.40 (preprogram), $788.26, and $582.22 in 1996, 1997, and 1998, respectively. Volume of pesticide applied decreased a mean of 86.3% on the four sites not receiving cover sprays and increased 2.3% at site 2 (still using cover sprays) in 1997. In 1998, pesticide volume was reduced an average of 85.3% at all five sites compared with preprogram levels. The majority of insect pest problems were corrected using spot sprays of insecticidal soap or horticultural oil or by physical means such as pruning. One-third of the woody plant material on the commercial and institutional sites consisted of holly, juniper, and azalea. The most prevalent pests encountered were mites (Tetranychidae), aphids, lace bugs, scales, whiteflies, and Japanese beetle. Spiders were the most abundant group of predatory arthropod and ants, green lacewings, and lady beetles were also well represented in the managed landscapes.     

Green manures of oat,rape and sweet corn for reducing common root rot in pea (Pisum sativum) caused by Aphanomyces euteiches

Green manure crops of sweet corn, soybean, alfalfa, snap bean, rape, pea and of the two oat cultivars Dane and Troy were incorporated into the same soil and containers in which the crop had grown for five weeks. The soil was then evaluated for suppression of common root rot (Aphanomyces euteiches) of pea grown in infested pasteurized and non-pasteurized soils in the greenhouse. Pea biomass reduction and a plant bioassay for A. euteiches were used to measure the green manure suppression of disease. Green manures of sweet corn cv.Jubilee, oat cv.Troy, and rape cv.Humus significantly reduced pea biomass losses over the non-amended control soil treatments. Oat cv.Troyand sweet corn cv.Jubilee green manures significantly reduced inoculum density of A. euteiches over the corresponding fallow controls in inoculated pasteurized soil by 87% and 76%, respectively, and in inoculated non-pasteurized soil by 67% and 66%, respectively. Only the green manure of oat cv. Troy reduced inoculum density significantly below fallow.     

Seasonal Fluctuations of Soil and Tissue Populations of Ditylenchus dipsaci and Aphelenchoides ritzemabosi in Alfalfa

Population dynamics of A. ritzemabosi and D. dipsaci were studied in two alfalfa fields in Wyoming. Symptomatic stem-bud tissue and root-zone soil from alfalfa plants exhibiting symptoms of D. dipsaci infection were collected at intervals of 3 to 4 weeks. Both nematodes were extracted from stem tissue with the Baermann funnel method and from soil with the sieving and Baermann funnel method. Soil moisture and soil temperature at 5 cm accounted for 64.8% and 61.0%, respectively, of the variability in numbers of both nematodes in soil at the Big Horn field. Also at the Big Horn field, A. ritzemabosi was found in soil on only three of the 14 collection dates, whereas D. dipsaci was found in soil on 12 dates. Aphelenchoides ritzemabosi was found in stem tissue samples on 9 of the 14 sampling dates whereas D. dipsaci was found on all dates. Populations of both nematodes in stem tissue peaked in October, and soil populations of both peaked in January, when soil moisture was greatest. Numbers of D. dipsaci in stem tissue were related to mean air temperature 3 weeks prior to tissue collection, while none of the climatic factors measured were associated with numbers of A. ritzemabosi. At the Dayton field, soil moisture plus soil temperature at 5 cm accounted for 98.2% and 91.4% of the variability in the soil populations of A. ritzemabosi and D. dipsaci, respectively. Aphelenchoides ritzemabosi was extracted from soil at two of the five collection dates, compared to extraction of D. dipsaci at three dates. Aphelenchoides ritzemabosi was collected from stem tissue at six of the seven sampling dates while D. dipsaci was found at all sampling dates. The only environmental factor that was associated with an increase in the numbers of both nematodes in alfalfa stem tissue was total precipitation 1 week prior to sampling, and this occurred only at the Dayton field. Numbers of A. ritzemabosi in stem tissue appeared to be not affected by any of the environmental factors studied, while numbers of D. dipsaci in stem tissue were associated with cumulative monthly precipitation, snow cover at time of sampling, and the mean weekly temperature 3 weeks prior to sampling. Harvesting alfalfa reduced the numbers of A. ritzemabosi at the Big Horn field and both nematodes at the Dayton field.