Biological control in home gardens and landscapes

Wiedenmann, R. and A. Wegeng

In collaboration with scientists at Purdue University, we trained nearly 400 Master Gardeners in Illinois and Indiana about biological control and using it in home gardens and landscapes. In addition, we supervised gardeners that conducted research projects in their gardens. In one test, gardeners released commercially available Trichogramma wasps weekly against cabbage pests, and significantly reduced numbers of cabbage worms. In another test, spraying nematodes against iris borer appeared to reduce numbers of borers, but reductions were not significant. Both tests will be repeated in 2000.

Biological control of Alfalfa Blotch Leafminer

Wiedenmann, R. and M. Martinez (INRA-France)

I searched for parasites of alfalfa blotch leafminer in its native range of Europe during my sabbatical leave. I collected nearly 500 leafminer larvae and reared over 50 parasitic wasps from the leafminers. None of the parasites were returned through quarantine in the US, due to permits not being obtained in time. Collaborators in Minnesota found parasites in Ontario and those are being reared for release in 2000.

Biological control of Purple Loosestrife

Wiedenmann, R. and D. Voegtlin, S. Post, A. Wegeng

In 1999, we raised and shipped ~ 500,000 adult Galerucella leaf-feeding beetles to cooperators for release against purple loosestrife in approximately 120 Illinois wetland sites. Cooperators raised 100,000 additional beetles at their own sites. We are seeing success at several Illinois sites. Near Illinois Beach State Park, beetle feeding reduced flowering to 5-10% of loosestrife plants, and reduced weed densities. In Savanna, large numbers of Galerucella caused great impact against loosestrife populations, with thousands of dead and stressed plants within 1/4 mile of release sites, and beetles dispersed over 1/2 mile away.

Broccoli pest management with cultivars

Eastman, C. and C. Velasquez (UIUC), J. Masiunas (UIUC), M. Kushad (UIUC), D. Liu (UIUC), C. Carpio (Pan American School of Agriculture, Honduras)

Brassicas such as broccoli and cabbage contain secondary plant compounds called glucosinolates that are part of these plants' chemical defenses against herbivores, plant pathogens, and weeds. Field experiments with new broccoli cultivars that differ in glucosinolates are being conducted in spring and fall plantings at the University of Illinois Vegetable Crops Farm (Champaign) to determine their effects on major insect pests and natural enemies. In a fall 1999 experiment, numbers of imported cabbageworms and diamondback moth larvae were very low overall and were similar on the two cultivars evaluated.

Control of Asian longhorn beetle

Solter, L. and J. Cate and M. Hatab (Integrated BioControl Systems, Inc., IN), L. Hanks (UIUC), M. McManus and M. Keena (USFS, CT)

Establishment of the Asian longhorn beetle in Illinois requires that control methods be studied, especially should eradication efforts be unsuccessful. Four species of nematodes were tested against Asian longhorn beetle larvae. All four species successfully invaded the ALB larvae and reproduced. One species, Heterorhabditis marilatus, was especially successful at killing the host and producing offspring. Further investigations are being planned.

Control of the gypsy moth in Illinois

Solter, L. and K. Higgs

Outbreaks of the gypsy moth, a forest and shade tree defoliator have occurred in several northern counties in Illinois. Collections of gypsy moth egg masses are being made to determine whether the invading populations harbor insect pathogens that might be useful for biological control. In particular, the presence of the fungal pathogen, Entomophaga maimaiga, is being investigated.

Cultural practice effects on broccoli

Eastman, C. and J. Masiunas (UIUC), M. Kushad (UIUC), D. Liu (UIUC), C. Carpio (Pan American School of Agriculture, Honduras)

Alternative cultural practices using living and artificial mulches are being evaluated in spring and fall field experiments at the University of Illinois Vegetable Crops Farm (Champaign) to determine their influence on weeds, insect pests, plant yield, and plant glucosinolate levels. In a fall 1999 experiment, broccoli grown in black plastic mulch developed more quickly and had higher numbers of imported cabbageworms than did broccoli grown in a living mulch or with conventional tillage.

Fungus gnats and natural enemies in greenhouse floriculture production

Zaborski, E. and R. Cloyd (UIUC)

Fungus gnats are an important insect pest in greenhouse floriculture production. The use of insecticides to control fungus gnats is costly, and raises concerns about worker safety, environmental contamination and insecticide resistance. Several natural enemies have been identified that might be used to manage fungus gnat populations in greenhouses. However, their use has not been widely adopted because of uncertainties about their efficacy and a lack of information about their use under different conditions. We are studying their effectiveness with different growing media and watering regimes.

Horseradish pest management and productivity

Eastman, C. and W. Chen and UIUC cooperators

Illinois leads the nation in horseradish production, but in the last few years the state's output of this cruciferous root crop has been seriously affected by disease and declining yields. At the request of the Horseradish Growers of Illinois, researchers at the Survey and University of Illinois have formed a collaborative team with UI-Extension and the growers to take a multi-disciplinary approach to solving these problems. Initiated in fall 1999, the research team now includes expertise in plant breeding, plant pathology, entomology, weed management, plant nutrition, tissue culture, and soil fertility. The group has field projects planned for spring 2000 and is working to find additional resources to support the research.

Improving forage alfalfa persistence in Illinois

Zaborski, E. and E. Armbrust, G. Bollero (UIUC)

Producers have reported declining persistence of forage alfalfa stands. Stand persistence is important because stand establishment is expensive. The influence of many factors on stand persistence, such as soil characteristics, insect pests, diseases, weeds, weather conditions, and management practices, have been studied individually. However, these factors may interact in important ways to influence stand persistence. We are leading a multistate effort to understand the interactions of these factors with the goal of developing integrated management strategies to improve stand persistence.

Influence of insecticides and crop residues from genetically modified corn on soil invertebrates, decomposition, and nutrient cycling

Zaborski, E. and L. Soeken

Few studies have been conducted to understand the ecological significance of the widespread adoption of genetically engineered crops. Corn has been modified to express an insecticidal toxin from the Bacillus thuringiensis bacteria as protection against the European corn borer and is being planted widely in Illinois. Soil invertebrates and other decomposers, which mediate soil processes such as nutrient cycling and soil formation, rely on crop residues for food and energy. We are studying how crop residues from Bt corn influence soil invertebrates and the important soil processes they mediate.

Migration & dispersal of biota on web

Kampmeier, G. and S. Isard (UIUC), Spencer, J. and NCR-148 members

The movement of biota over long distances as influenced by atmospheric motion systems is featured at http://www.inhs.uiuc.edu/cee/movement/. Knowledge of movement of insects and plant pathogens is key to the success of integrated pest management programs. These pages detail on-going research, collaborations, symposia, and annual meetings held by the NCR-148, a North Central Regional Committee with membership from across North America, and the site provides a clearinghouse for movement and dispersal related organizations and issues.

On-farm experiments with glucosinolate-rich crucifers

Eastman, C. and J. Masiunas (UIUC), M. Kushad (UIUC), J. Aguyoh (UIUC)

On-farm experiments with cultivars of broccoli, cabbage, and horseradish differing in glucosinolate levels have been initiated for spring planting in northern and southwestern Illinois. A major objective is to determine if these cultivars are less susceptible than standard low-glucosinolate cultivars to the range of insect pests that attack these crops. A second objective is to evaluate the popularity of these new cultivars with consumers at roadside markets. Glucosinolates, in addition to their pest management qualities, have anti-cancer properties that may benefit human health. New cultivars with higher glucosinolate levels are being developed commercially for these added health benefits.

Rootworm abundance in soybean cultivars

Levine, E. and J. Spencer, M. Gray (UIUC), R. Nelson (UIUC), R. Hammond (OH State Univ.), C. Pierce (UIUC), S. Isard (UIUC)

Studies with different soybean cultivars have revealed that significantly higher densities of western corn rootworm beetles are found on some soybean lines than on others. Beetle abundance was particularly low in some of the lines we examined which suggests that we may be able to exploit such cultivars to reduce egg-laying in locations where they are planted.