Native Habitat Restoration, Sustainable IPM and Beneficial Insect Conservation

Native Habitat Restoration, Sustainable IPM and Beneficial Insect Conservation

Summary

Substantial progress was made with continued collection of data on the incidence and abundance of pest, beneficial insects and mites at native habitat restored (NHR) and conventional (native habitat reduced) vineyards. Trends of reduced pest abundance and increased beneficial insect diversity and abundance occurred in NHR vineyards in 2011 and 2012. Diversity and abundance of butterflies was also greater in NHR vineyards. Trapping data obtained from more than 70 native flowering plants identified a subset of about 20 species that consistently attract large numbers of a wide variety of beneficial insects.

Objectives/Performance Targets

1.Select four demonstration (Native Habitat Restoration: NHR) and four (paired) control vineyards without NHR.

Four NHR demonstration and four (paired) control vineyards (without NHR) were selected and used in 2011. An additional two vineyards were used in 2012, one in Walla Walla (new control vineyard) and one at Red Mountain (new NHR vineyard). Four viticultural sub-areas within the south central Washington wine grape growing area were used for these sites to give a broader spread of climatic, vegetational and entomological variation.

A)Columbia Gorge AVA: Wine grapes in this sub-area are exposed to a
more moderate and humid climate (adjacent to the Columbia River). NHR site – Klickitat Winery (Robin Dobson) Syrah (two acres). NHR has been implemented at this site for 12 years. Control site – Dry Hollow (Jose Flores) Syrah (five acres).

B)Columbia Valley AVA: Wine grapes in this sub-area exposed to hot and dry growing conditions. NHR site – White Heron Cellars (Cameron Fries) Malbec (12 acres). NHR has been implemented at this site for eight years. Control site – Jones of Washington (Greg Jones) Malbec (six acres).

C)Walla Walla Valley AVA: Wine grapes in this sub-area exposed to hot and dry conditions and unique terroir. NHR site – Woodward Canyon Estate Vineyards (Rick Small) Cabernet Franc (six acres). NHR has been implemented at this site for five years. NHR sitev- Sevein Hills (Jon Davies) Cabernet Franc (four acres). This was used as a control site in 2011, but habitat improvements now make this vineyard ‘transitional’ to NHR. Control sit e- River Rock Vineyards (Dana Dibble) Cabernet Franc (four acres). New control site selected in 2012.

D)Red Mountain AVA: Wine grapes in this sub-area exposed to hot and dry conditions and unique terroir. NHR site – Ciel du Cheval Winery (Jim Holmes) Cabernet Sauvignon. NHR is being implemented at this site (two years). NHR site – Upchurch (Dick Boushey) Cabernet Sauvignon. Control site- La Coye Winery (Dick Boushey) Cabernet Sauvignon.

2.Monitoring of pest and beneficial arthropods in NHR and control vineyards (April-September) to provide data on abundance and seasonality of pests, natural enemies, butterflies and bees.

Monitoring of pest and beneficial arthropods in the 10 vineyards listed above was conducted during May – September 2012. Some of these data are presented in this report.

3.Establish additional refugia and native perennial ground cover plots in demonstration vineyards. Aim to increase native plant refugia area to 20-25%. Aim to establish at least three ground cover species in each vineyard.

For five of the six selected NHR vineyards there is no need to establish additional refugia/ground covers because each already has a long history (8-11 years) of native habitat restoration/encouragement (Klickitat Winery, White Heron Cellars, Woodward Canyon Estate, Upchurch, Sevein Hills). The NHR status of the remaining demonstration vineyard (Ciel du Cheval) is improving with native plants being established.

4.Conduct survey of abundance of pest natural enemies attracted to flowering native perennials in south and central WA. Collect data for 30-50 potential candidates for ground covers and refugia plantings.

This survey commenced in 2010 and continued in 2011 and 2012. To date we have surveyed the abundance of beneficial insects associated with 103 species of flowering plants, mostly native perennials. Some of these data are presented in this report.

5.Establish native perennial ground cover candidates in field plot trial at WSU-Prosser for evaluation as natural enemy attractants. Select at least 15 species.

Three groups of replicated native plant plots have been established at WSU-Prosser comprising 12 plants. Difficulties with some native plant species prevented a higher number being established.

6.Mass rear and release selected butterfly species in NHR vineyards using the Sustainable Prisons program.

In retrospect, the timing of this objective (commencing after six months of the project) is premature. Time is needed to determine the butterfly fauna of each vineyard before commencing a rear and release program. This objective is better timed to conduct in year 3 (2013). Preparations for conduct of this objective were made in 2011-12 with initial evaluations of vineyard butterfly fauna and establishment of rearing protocols, etc. with the Washington State Penitentiary at Walla Walla (WWP), which is the facility to be involved in this project. Some preliminary rearing programs were conducted by inmates at the WWP in 2012 to test feasibility of the concept.

7.Establish and maintain NHR website regularly detailing progress and providing information for other vineyards wishing to adopt the program.

A website devoted to this project was established in spring 2011 and may be found at:
http://www.wavineyardbeautywithbenefits.com/ In addition, a Facebook page was also set up to provide timely information:
http://www.facebook.com/pages/Vineyard-Beauty-with-Benefits-Restoring-Habitat-for-Beneficial-Insects/112777002135559?sk=wall

Accomplishments/Milestones

Substantial progress was made in 2012 in 1) establishing and monitoring NHR and control vineyards for pest and beneficial arthropods, 2) evaluating beneficial insect attraction to native plant species, and 3) establishing replicated plots of selected native plant species and monitoring beneficial insect attraction.

Investigate native perennial flowering plants for attractiveness to beneficial insects and practicality for use as vineyard covers and refugia

Ground covers and refugia confer a number of benefits on vineyards, including the attraction and retention of beneficial insects. A WSU/NCSFR funded study during 2005-08 demonstrated the value of some species of non-endemic annual flowering plants as ground covers to attract and retain various beneficial insects in south central Washington vineyards, with no adverse effects on vine growth. However, germination and survival of the cover crops was generally poor, due to the characteristically dry climate of south central Washington. A recent study in Michigan compared the attractiveness of selected perennial native plants and exotic annual plants to beneficial insects and found many native plants to be just as attractive, or more attractive than the exotics. The use of native perennial plants for ground covers and refugia has several benefits, including better adaptation to the local environment, aiding local biodiversity and avoidance of annual establishment. In addition, native perennials may provide overwintering sites for beneficial arthropods. To restore native habitat refugia to Washington vineyards to enhance IPM and biological control, plant species with optimal attraction to predators and parasitoids of grape pests need to be selected. No information is available on the attractiveness of native flowering perennial plants to beneficial insects in south central Washington.

One hundred and six species of flowering perennial plants were evaluated for beneficial insect attraction in 2011 and 2012 field studies. The vast majority of these are native, and all plants were growing wild in natural shrub-steppe landscapes in the Yakima Valley and nearby areas. Studies were primarily conducted at five to six sites near Yakima, Prosser and the Tri-Cities during April-November. The number and identity of beneficial insects attracted to different plant species was assessed using clear sticky traps (12 x 4 inches) placed either on the flowering plant or immediately adjacent to the plant. Control traps, placed on bare ground, rocks or dry non-flowering vegetation were also positioned near target plants. The major types of beneficial insects assessed are shown in Table 1. All of these groups play a role in regulating grapevine insect and mite pests in eastern Washington vineyards. For each assessment a single trap was used to assess attraction to each of three separated (at least five meters) individual plants. Traps were left in the field for one to three weeks, retrieved, taken to the laboratory, stored and examined later for beneficial insects under the microscope. Most plants were evaluated at multiple sites. Insects were identified to species or family, counted and recorded. All data were converted to means per trap per trapping period.

Results

More than 1,000 traps were deployed on 103 species of flowering perennial plants during April-November 2011 and 2012. Of these in 2011, 73 species were evaluated on at least three occasions and data from these are summarized here (Fig. 1).

The top ten native plant species, judged by their attractiveness to all groups of beneficial insects, are shown in Fig. 2.

Sagebrush (Artemesia tridentata), somewhat surprisingly, was ranked the number 1 species, but this was due to its attraction to large numbers of parasitic wasps which accounted for >90% of the beneficial insects attracted. Similarly, the number 2 species, Gray Rabbitbrush (Ericameria nauseosus) was also strongly attractive to parasitic wasps (>90% of attracted insects). The third species, Oregon sunshine (Eriophyllum lanatum), was also biased towards one group, but this time it was beneficial flies (>80%). Slender Hawksbeard (Crepis atribarba) was also heavily biased towards flies (>80%), but the remaining species in the top ten were more balanced in their attraction to a wider variety of beneficial insects. Western clematis (Clematis ligusticifolia), Northern buckwheat (Eriogonum compositum), Showy milkweed (Asclepias speciosa) and Snow buckwheat (Eriogonum niveum) attracted large numbers of beneficial insects from all eight groups shown in Table 1 (Fig. 3). Parasitic wasps and beneficial flies still made up the majority of insects attracted to these four species, although Clematis attracted large numbers of predatory bugs (Fig. 4) and Northern buckwheat was the best plant for attracting ladybeetles. Milkweed was the best plant for attracting bees.

When all groups of beneficial insects are combined, the mean number collected per trap in 2011 ranged from a low of eight (Big-headed clover) to a high of 505 (Sagebrush) for the 73 plant species for which there are data for at least three trapping periods. The top ten species ranged from 150-505. The top 20 species had means >75. About half of the 73 species trapped means of less than 50 beneficial insects. However, some of these may have value in attracting specific beneficial insects (e.g. #41, Stinging nettle attractive to predatory bugs, Fig 4).

To date, results from 10 of the ~ 100 plant species evaluated in 2012 have been analyzed. Snow buckwheat, Northern buckwheat, Gray Rabbitbrush, Milkweed, Western clematis and Oregon Sunshine all produced results similar to those obtained in 2011. Yarrow (Achillea millefolium), ranked # 9 in 2011 (mean of 170 beneficial insects/trap), improved considerably in 2012 with 432/trap (80% parasitic wasps). Completion of 2012 species attraction analysis is expected before spring 2013.

Evaluation of the pest and beneficial insect fauna associated with habitat-enhanced and habitat-reduced vineyards

Ten commercial vineyards are cooperators in this multi-season study which commenced in spring 2011. A pair of vineyards was identified and selected in each of the Columbia Gorge, Columbia Basin, Walla Walla and Quincy-Mattawa viticultural areas. In 2012, an additional NHR vineyard was monitored in the Columbia Basin and Walla Walla areas. Each area had one or two ‘native habitat-enhanced’ (VH) and a ‘native habitat-reduced’ (C) vineyard. Habitat-enhanced vineyards are situated close to natural areas with current management practices designed to maximize colonization of native plants in and/or around vineyards. Habitat-reduced vineyards are situated away from natural areas and colonization of native plants has not been encouraged and usually actively discouraged. Monitoring of pest and beneficial insect and mite populations commenced in all vineyards in May, continuing at two-weekly intervals until September. On each visit leaf samples were taken from grapevines and sticky yellow traps were placed in the vineyard. Leaves were examined in the laboratory for pests and beneficial insects and mites as were sticky traps. Additional sticky traps were placed in native habitats present adjacent to the habitat-enhanced vineyards.

Results

Inventories of flowering plants and butterflies were obtained for each vineyard site during fortnightly visits in 2012 (Table 2).

As expected, the habitat-enhanced vineyard sites had greater numbers of flowering plant species than habitat-reduced sites. Similarly, most habitat-enhanced vineyards appeared to support greater numbers of butterflies, both in abundance of individuals and species diversity.

Beneficial insect abundance as determined by sticky trapping was significantly greater at habitat-enhanced than habitat-reduced vineyard sites (Fig. 6).

This trend was evident in all major beneficial insect groups when examined separately, including the important grape leafhopper parasitoids, Anagrus spp.

Examination and analysis of beneficial insect abundance and diversity in habitat areas around the habitat-enhanced vineyards indicated that some beneficial insect groups dispersed more effectively to the vineyard than others. For example, parasitic wasp abundance was substantially greater in surrounding habitat than in two ‘enhanced’ vineyards at Red Mountain (Fig. 8). In contrast beneficial beetles and bugs in the Columbia gorge were more abundant in the habitat-enhanced vineyard than in surrounding habitat (Fig. 9).

Grape pest levels were generally low in all vineyards, but there was a clear trend for greater incidence of mites, leafhoppers, mealybugs and scale insects in habitat-reduced vineyards compared to habitat-enhanced vineyards (Figure 10). The numbers of beneficial mites (predators of rust and spider mites) on leaves did not differ greatly between habitat-reduced and enhanced vineyards, suggesting beneficial insects respond better to habitat improvement.

These data support the hypothesis that adjacent native habitats supporting a diverse community of native plants can be an important source of some groups of predators, parasitoids and pollinators, instrumental in providing effective and sustainable ecosystem services (e.g biological control of grape pests) in vineyards. In addition to providing direct and tangible benefits to viticulture, vineyard habitat restoration also has the potential to help conserve threatened flora and fauna, including threatened native bees and butterflies. While butterflies were more abundant and diverse in habitat-enhanced vineyards, populations were generally small. Providing specific plants needed by specific butterfly species for development of immature stages has the potential to make vineyards suitable habitats for a number of eastern Washington butterflies.

Our research on attraction of beneficial insects to native flowering plants and the impact of native habitat on vineyard IPM is close to identifying landscape templates for eastern Washington vineyards that optimize beneficial insect populations and minimize grape pests. These templates will also have considerable benefits for wildlife that are dependent on native flora like bees and butterflies.

What work is left to do?

Beneficial insect attraction to native plants: Another season (2013) of evaluating beneficial insect attraction to the 30-50 highest ranked species identified in 2011 and 2012. Selected high ranking species with potential as vineyard ground covers will begin in-vineyard evaluation.

Comparison of habitat-enhanced and conventional vineyards: Monitoring and evaluation of pest and beneficial insects in these vineyards will continue in 2013. Butterfly populations in vineyards will be studied in greater depth. Candidate local species for possible introduction to habitat-enhanced vineyards will be selected and a program established with Washington State Penitentiary for mass-rearing.

• Table 2. Number of flowering plants and butterflies at each vineyard site in 2012
• Figure 2. The top ten most attractive native plants for beneficial insects in 2011
• Figure 4. The seven best flowering plants for attracting predatory bugs in 2011
• Figure 6. Abundance of all beneficial insect species in habitat-enhanced and habitat-reduced vineyards in 2012
• Figure 8. Abundance of parasitic wasps in a conventional (habitat-reduced) and 2 habitat-enhanced vineyards and adjacent habitat at Red Mountain (Columbia Basin) in 2012
• Table 1. Beneficial insects important in viticulture assessed for their attraction to flowering plants
• Figure 3. relative attraction of different groups of beneficial insects to Northern buckwheat, Western clematis, Milkweed and Snow buckwheat flowers in 2011 (top 2-3 groups indicated)
• Figure 7. Abundance of Anagrus spp. in habitat-enhanced and habitat-reduced vineyards in 2012
• Figure 10. Incidence of grape leaf pests (mites, leafhoppers, mealybugs, scale insects) in a conventional (habitat-reduced) and 2 habitat-enhanced vineyards at Walla Walla in 2012
• Figure 1. Summary of relative attractivity of 73 species of native plants to all groups of beneficial insects
• Figure 9. Abundance of beneficial beetles and bugs in a conventional (habitat-reduced and 2 habitat-enhanced vineyards and adjacent habitat in the Columbia Gorge in 2012
• Figure 5. The five best flowering plants for attracting ladybeetles in 2011
• WSAREFig 6.pdf

Impacts and Contributions/Outcomes

This research program will benefit the Washington wine grape industry by improving the efficacy and sustainability of conservation biological control of vineyard pests by restoring native habitats and associated communities of natural enemies. This will result in reduced pesticide use, production costs and environmental contamination. In addition, our research will feature and demonstrate for the first time in the western U.S., the role that agriculture can play in insect conservation. Washington vineyards will be shown to have the potential to provide habitat and refugia for threatened and charismatic insects like native butterflies and bees as well as native flora. Merging the interface between agricultural production, sustainable biological control and conservation of threatened insects and flora is likely to bring substantial benefits to grapegrowers and regional communities. In addition to low input, sustainable biological control, our program will highlight marketing and tourism opportunities for wineries and the viticultural industry as a whole. Butterflies and bees may become the symbol of green viticulture in Washington State, playing a significant role in increasing sales and tourism.

Collaborators: