- Additional Plants: ornamentals
- Production Systems: integrated crop and livestock systems
Environmental and public health concerns have led to public demand for critical reassessment of current pest management tactics in urban surroundings, but have not reduced high aesthetic standards for urban landscapes and recreational turf areas. Pesticides and fertilizers are important potential pollutants of surface waters in urban areas. In order for landscape maintenance firms to successfully implement IPM strategies, clients must perceive that service is being provided even when a scouting-based diagnosis calls for no chemical treatment. Therefore, both providers and consumers were targeted for educational programs on the benefits of IPM in urban landscape systems. These programs were intimately tied to research efforts developing appropriate best management strategies in the Georgia Station Research and Education Garden. A Research/Extension team of eight interdisciplinary Ornamentals Working Group participated in this effort.
Twenty mini-landscapes were constructed in the Research and Education Garden at the Georgia Experiment Station. Each mini-landscape contains woody ornamentals, annual and perennial bedding plants, and turfgrass to simulate a home landscape. Portions of each contain either woody plants alone or bedding plants alone to evaluate the effect of each type of plant material on pest susceptibility. Plots are mirror image construction to allow evaluation of the cultural variable shade . Design was a split-split plot with management strategy as the main plot, randomized with four replications.
Management strategies included
1. Full traditional management in cooperation with TrueGreen ChemLawn’s Research Facility in Douglassville, GA
2. A scouting-based application program
3. Resistant plant-based landscapes
4. Untreated control plots with susceptible cultivars and, during 1997
5. Landscapes managed using products typically available to homeowners.
Plant Material and Key Pests included:
Azaleas: ‘Delaware Valley White’ and ’Plumleaf’; susceptible and resistant, respectively to azalea lace bug, Stephanitis pyrioides (Scott)
Hollies: ‘Savannah’ and ‘Nana’ burfordii; susceptible and resistant, respectively to two lined spittlebug, Prosapia bicincta Say.
Turfgrass: ‘Common’ centipedegrass and ‘Emerald’ zoysiagrass; susceptible and resistant, respectively to two lined spittlebug.
Bedding plants: New guinea impatiens and ‘Homestead Purple’ verbena. “Resistant plants” were those that had undergone a brushing treatment in the green house prior to transfer to the landscape. Previous research had shown that this form of growth regulation may also confer pest resistance. Pests evaluated on bedding plants were aphids, mites, whiteflies, thrips, and leafhoppers.
Ground-dwelling beneficial insects, mites and spiders were monitored in turf and ornamental beds using standard pitfall traps; beneficials were also evaluated on bedding plant foliage using visual inspections. Insect populations were assessed at intervals throughout the season. Damage ratings and plant quality data were also recorded.
Population levels of azalea lace bug and two lined spittlebug were influenced by management strategy and by the cultural variable shade during 1996 and 1997. Plots based on resistant plant material had no lace bugs or spittlebugs during this study. Plots with susceptible plant materials and no intervention supported high populations of both pests. Traditional management significantly reduced lace bug numbers, while scouting-based or targeted management supported intermediate levels of key pests.
Lace bugs were more common in plots in artificial 50% shade than in full sun. Spittlebugs were more abundant in the shaded half of plots during 1996 and slightly more common in unshaded plots during 1997.
Subplot, or the presence or absence of either woody or herbaceous plant material did not affect the abundance of either pest species on woody plants, but did affect plant quality and damage ratings for herbaceous plants. Annual bedding plant quality was reduced in plots exposed to full sun, although aesthetic quality of the perennial verbena was similar in both sun and shade. Few differences in pest population numbers were noted in bi-weekly samples. Winter survival of turfgrass (centipedegrass) was influenced by both shade and management strategy during 1995/1996, but not during 1996/1997. Ground-dwelling staphylinids, carabids, cicindellids, formicids, and arachnids were similar in both sunny and shaded plots and were unaffected by management strategy.
Acceptable plant quality was achieved in traditional, targeted, and resistant plant-based mini landscapes, although chemical inputs and man-hours required to maintain aesthetic quality varied. Simple shade, without the beneficial arthropod fauna characteristic of natural overstory shade, favored the development of lace bug populations, and sometimes enhanced population development of spittlebugs. Location of mini-landscapes in the Research and Education Garden provided a forum for immediate transfer of research results to a diverse clientele.