Monitoring Summary: Spider mites, thrips and flea beetles are up. But so are many beneficials. Pest Focus: Flea beetle are a hopping nuisance! Beneficial Focus: How can you have more hover flies?
Monitoring Updates Updates are from select sites within the past two weeks, providing generalizations about pests. Levels can vary greatly between farms, so make any pest management decision based on data from your own farm!! North Island: Qualicum to Campbell (4 farms), Mid Island: Nanaimo to Mill Bay (4 farms), South Island: Victoria and Saanich Peninsula (3 farms).
Carrots: (4 North, 4 Mid, 2 South) Carrot rust fly were present at 3/10 farms this monitoring period. All farms were below the management threshold of 0.1 flies/day/trap this period. Rust fly pressure often increases in the fall, so monitor your own fields with this resource.
Brassicas: (4 North, 3 Mid, 2 South) Caterpillars: Caterpillars continue to be observed on all farms this period. All three species were observed, and overall infestation rates varied from 7-64%. Average infestation across all plantings was 35%, with high variability between farms. The most commonly observed caterpillars were diamond back, followed by imported cabbage worm, and only two fields had loopers. Many diamondback pupae and imported cabbage worm eggs were observed. Substantial numbers of caterpillar parasitoids and caterpillars killed by insecticides were observed. Learn more about caterpillars, management and monitoring strategies using thisresource.
Aphids:Cabbage aphids were present on all farms again this monitoring period. There continues to be high variation in aphid levels, with rates of infestation of 7-75%. In some fields colonies were small, and restricted to outer leaves, while in other farms large colonies were contaminating the harvest. This variation can be caused by crops type and stage, levels of beneficial insects and management actions. Some farms have high numbers of parasitized aphids, hover fly larva and entomopathogenic fungi, and the beneficials are keeping new colonies in check. On other farms there are not sufficient beneficial insects to prevent contamination of the crop and insecticides are required. Monitor your own crops for both aphids and beneficials to determine if management actions are needed. Learn more about cabbage aphids here, and learn about hover flies and enhancing biocontrol in the focus section.
Flea Beetle: Flea beetles continue to be a problem, and were present in 6/9 sites. Infestation levels were at 14-100%, with two farms at 100% infestation. Different varieties and crop stages differ in their attractiveness to flea beetle and their susceptibility to economic damage. While some plants displayed heavy feeding damage, other crops in the same farm had only light damage. Learn more in the focus section.
Cabbage Maggot: No plants were checked for cabbage maggot this period. Remember that small plants are most susceptible to maggot damage, and protect fall transplants, especially in sites that have had issues in the past, and if soil is cool.
Thrips: 8/9 fields had thrips present, at levels of 3-100% infestation. High thrips populations can cause plant damage and reduce yields. Thrips numbers are expected to increase with hot weather. Learn more about thrips here.
Beneficials: Many aphid predators are present, including aphid mummies and parasitoid wasps, hover fly eggs, larva and adults, aphidoletes larva. We also observed lacewing eggs and adults. Caterpillar parasitoid wasps and pupae were also observed, as were predatory wasps hunting for caterpillars in the brassica fields.
Apple maggot eggs in apple
Apples: (3 North, 2 Mid, 1 South) Codling moth: All farms caught codling moths in pheromone traps this monitoring period, with numbers increasing in the mid and north island, while declining in the south island. Numbers ranged from 0.25 - 3.5 moths per trap/week. 3 farms were above the suggested economic threshold for controlling codling moth of 2 or more moths caught two weeks in a row. Monitoring on your own farm to understand what codling moth are doing in your area. Fruit infestation were observed on several farms, as well as dropped fruit. Farm sanitation is an important part of managing codling moth. More info on codling moth here.
Apple Maggot: Apple maggot was present in 7/8 farms and numbers continue to increase. Rates were 0.5 - 69 flies per trap/week and varied greatly between farms. Apple maggot egg laying stings are being observed in fruit. Apple maggot can cause considerable crop loss. Learn more here.
Caterpillars: Leafrollers were observed at low levels (<3%) on 2/6 farms.
Berries: (Blueberry 5, Raspberries 6, Strawberries 8) SWD infested berries were observed in strawberry, raspberry and blueberry this period.
Caterpillars: Leafrollers were observed at low levels (5%) in strawberry fields. While caterpillars present during harvest can be a contaminant, established plants can easily handle low levels of leaf feeding at this time. Learn more about caterpillars in berry crops here.
Aphids: Aphids were present in 3/5 blueberry, 6/8 strawberry and no raspberry fields. Infestation levels in blueberry fields were low, with aphids present on only 1-4% of leaves. Aphid infestations in strawberries had declined to 5-30% of leaves infested with small colonies. Many aphid predators continue to be present. Aphids are a concern in berries because they can spread viruses. Learn more about blueberry scorch virus and aphid monitoring in berries here.
Mites: Spider mite levels in strawberries varied between farms again this monitoring period, but some infestations have increased in severity. Mites were present in 6/8 strawberry fields at rates of 5-80% leaf infestation. Spider mite predators were present in some fields. High spider mite populations in fields that will be overwintered can cause issues next season and the recent hot and dry weather can increase spider mite populations. Check your own fields to see if spider mite numbers are increasing, and remember to also check June bearing fields as leaves re-grow after renovation. Learn more about monitoring and managing spider mites here. And learn about spider mites in cucumbers here. No spider mites were observed in blueberries or raspberries.
Other Pests: Blueberry gall midge was present, as were thrips, stinkbugs, whitefly, and leafhoppers
Disease: Mummy berry is still present in blueberry fields. Learn more using this IPM guide.
Spotted wing drosophila (4 North, 4 Mid, 3 South)
SWD infested berries were observed in raspberry, strawberry and blueberry this monitoring period.
SWD were observed in hedgerow traps at similar levels to last period (1-7/trap) on 4 farms. SWD were also observed in blueberry, raspberry and strawberry traps. On some farms where raspberry harvest has ended, high levels of SWD are being captured in the trap - this mean they are actively looking for a new source of food, and are likely to spill over into adjacent crops. Male and female SWD were detected at equivalent levels. Males have spotted wings, making them easier to ID than females. The level of risk to crops from SWD is high and will continue to rise as we move into the fall. Berry fields with ripening fruit should be managing for SWD at this time. Learn more about SWD here.
Flea Beetle:Crucifer and Tuber Flea Beetles These hopping pests can be a serious issue in brassica and potato production. How do I ID?
Adults are small (2-3 mm) black beetles that hop when disturbed. Adult feeding damage creates many small holes (shot holes) on leaves. Crucifer flea beetle are shiny and black, while tuber flea beetles are fuzzy and black. Other flea beetle species can also be present. When does it occur?
Adults overwinter and move into fields in the spring. They feed, and lay eggs in soil at the plant base. The soil dwelling larva feeds on the roots, before a second round of adults emerge later in the season. The number of pest cycles will depend on the species and how long the season is, with increasing populations as the season progresses. What is at risk?
Adult crucifer flea beetle feeding on emerging brassica seedlings can kill plants and feeding on cruciferous salad greens can make then unmarketable. Crops vary in their susceptibility (see photo above of a heavily damaged broccoli leaf next to an untouched brussel sprout leaf). Tuber flea beetle larval feeding can make potatoes unmarketable, while very high levels of adult feeding damage can reduce plant vigor. How do I respond? - Monitor for flea beetle presence.
-Protect early season crops with row cover or insecticides, or delay planting until the first generation is past. - Consider using trap crops to attract flea beetles away from cash crops. -Manage alternate hosts (volunteer potatoes, mustard weeds, etc). - Destroy infested plant residues after harvest, including the below ground parts where the larva are. Beneficials?
Generalist predators (lacewing larva, damsel bugs) will feed on adults, while soil dwelling predators (rove beetles, ground beetles) and entomopathogenic nematodes will feed on larva. Learn More: Organic Management of Flea Beetle (lots of info on trap crops, and cultural practices) Small Scale IPM Guide for tuber flea beetle
BC Vegetable Production Guides: Brassicas, Potatoes
Benefical Focus
Hover fly (Syrphidae) Pollinators as adults and predators as larva! We have observed 21 different species in our iNaturalist project. Record the species on your farm!
How do I ID?
Adults mimic wasps and bees. They can be smooth or fuzzy, big or small and have a distinctive hovering flight. See some of the diversityhere. White eggs resemble a grain of rice, often laid near an aphid colony. Larva are legless and slow moving, while pupae resemble a rain drop. Why do I want them?
Larva consume hundreds of aphids during their development, making hover flies one of the most valuable aphid controls. They are present throughout the season, and adults are highly mobile, able to seek out aphid colonies. As well, the adults contribute to pollination! How do I attract them?
Adult hover flies are attracted to small flowering plants such as alyssum, dill, and yarrow. Research in California has demonstrated that 1-2 alyssum plants per 50 lettuce plants can support enough hover flies to keep the lettuce aphid free! Limiting broad spectrum insecticides and protecting natural areas surrounding your farm will support hover flies throughout the season. Learn More: Hover flies Biocontrol strategies video (12 minute) IDing hover flies vs caterpillars Habitat planning for beneficial insects (a great winter read!)
This newsletter is written on the traditional unceded territory of the K'ómoks First Nation. Our work is being carried out within the traditional territories of many nations inclusive of the Nuu-chah-nulth, Kwakwaka’wakw and Coast Salish traditions.
This project is brought to you by Bonnie Zand of Bonnie's Bugs IPM. Funding for this project has been provided by the Governments of Canada and British Columbia through the Canadian Agricultural Partnership, a federal-provincial-territorial initiative. The program is delivered by the Investment Agriculture Foundation of BC.
Opinions expressed in this document are those of the author and not necessarily those of the Governments of Canada and British Columbia or the Investment Agriculture Foundation of BC. The Governments of Canada and British Columbia, and the Investment Agriculture Foundation of BC, and their directors, agents, employees, or contractors will not be liable for any claims, damages, or losses of any kind whatsoever arising out of the use of, or reliance upon, this information.
