- Author: Surendra K. Dara
The spotted lanternfly (Lycorma delicatula) is an invasive pest in the United States that was first detected in 2014 in Pennsylvania. It is a pest of numerous cultivated and wild hosts. It can cause serious damage to apples, grapes, stone fruit, landscape trees, and others and can be a nuisance pest in urban areas.
Is California at risk?
It is predicted that many agriculturally important regions in California are at a high risk if this pest ever invades the state. California climate and a wide host range including both cultivated and wild species can support the establishment and spread of the spotted lanternfly. The tree-of-heaven, which is a favorite host of the spotted lanternfly, is an invasive tree that is spread throughout California and can serve as a source of infestation.
Who should be concerned?
Apples, cherries, grapes, peaches, pears, and roses are some of the commodities at risk in California that are valued at more than $7 billion. Spotted lanternfly is also a nuisance to the urban landscapes by infesting grapes, roses, and various species of trees.
What does this pest do?
Spotted lanternfly inserts its piercing and sucking mouthparts into plant tissues, feeds on nutrient-rich phloem sap, and produces large volumes of honeydew. Feeding depletes nutrients, reduces plant vigor, and yields. Sooty mold develops on honeydew and affects photosynthesis. Heavy infestations can kill the plant. When uncontrolled, populations build to hundreds or thousands on an individual plant.
What is its life cycle?
On the east coast, egg laying occurs in fall, nymphs start emerging in spring and mature to adults starting in summer. Eggs are covered by waxy protective material.
How to control spotted lanternfly?
Removing and destroying egg masses, applying biological and synthetic pesticides, and encouraging biocontrol agents are some of the control options. The first line of defense is to prevent its invasion and spread.
How can it get to California?
It can arrive as egg masses (mistaken for a splash of mud) or other life stages in/on packages, vehicles, and other inanimate objects moving from infested areas.
What should we do?
Since spotted lanternfly affects cultivated, landscape, and wild plants, both the farming community and the general public should be aware of it, its potential damage, and negative impact in California. All of us should be able to recognize the pest and report to the local agricultural commissioner or farm advisor offices.
This is a dynamic space various resources will be periodically added about this pest.
A quick overview of the spotted lanternfly biology, its damage to grapes, and potential control options (5 min)
A detailed overview of the spotted lanternfly, its damage, and control options (33 min)
Extension article in Pest News eJournal
Scientific article in the Journal of Integrated Pest Management
Compilation of research articles in Environmental Entomology
Current distribution in the United States
Establishment risk in the United States and globally published in the Journal of Economic Entomology
Website managed by the Northeastern IPM Center's resource to Stop SLF
Management guide from PennState Extension
Spotted lanternfly risk in California
- Author: Heather Scheck, Santa Barbara Ag Commissioner's Office
- Author: John Chitambar, California Department of Food and Agriculture
- Author: Surendra K. Dara, UCCE
Healthy red apple ice plant, Aptenia cordifolia. Photo by Heather Scheck, Santa Barbara Ag Commissioner's Office
A downy mildew caused by the oomycetous fungus, Peronospora mesembryanthemi Verwoerd has recently been confirmed by the USDA -APHIS from a red apple ice plant sample collected in San Diego. Since its first finding in San Diego County last summer, the disease has spread to Orange, San Bernardino, and Ventura counties and is now found in the Goleta area in Santa Barbara County. Peronospora mesembryanthemi was first reported from South Africa (Verwoerd, 1924) and later in the United Kingdom (Francis and Waterhouse, 1988) and New Zealand (McKenzie and Dingley, 1996), but has never been reported in North America. The host range of P. mesembryanthemi is thought to be limited to ice plants and it is currently found infecting the red apple ice plant, Aptenia cordifolia, the trailing ice plant or the pink carpet, Delosperma (syn. Mesembryanthemum) cooperi, and Lampranthus sp. in California. Both these ice plant species are native to southern Africa. Because of their environmental hardiness, ease of growing, and bright, colorful flowers, ice plants are grown as ornamental plants or found as groundcovers. However, the red apple ice plant is listed as an invasive plant by the California Exotic Pest Plant Council. It can sometimes grow like a weed.
Red apple ice plant overwhelming yucca plants. Photo by Heather Scheck, Santa Barbara Ag Commissioner's Office
Pathogen: Downy mildew appears as a mat of grey, blue, or brown fungal growth on the lower or both sides of leaves and other infected plant parts. Fungal growth consists of the asexual fruiting structures known as sporangia that are produced on sporangiophores, which are specialized hyphae. Downy mildew fungi cause systemic infection and grow internally in all plant parts. Infection rapidly spreads under cool and wet conditions. Windblown rain or sprinkler splashing spreads disperse sporangia and aid in the disease spread. Downy mildew fungi are obligate parasites of plants and most of them have narrow host range of one or just a few hosts.
Greyish sporulation of Peronospora mesembryanthemi on an ice plant. Photo by Jose Rodriguez, Soil and Plant Laboratory, Inc.
Downy mildew-infected red apple ice plant. Photo by Heather Scheck, Santa Barbara Ag Commissioner's Office
Severe downy mildew damage to an ice plant. Photo by Heather Scheck, Santa Barbara Ag Commissioner's Office
Damage: The rapid spread of P. mesembryanthemi through southern California could be from accidental movement of infected nursery stock. Severe damage with heavy or total loss of plantings is becoming common in southern California counties where the disease is currently found.
Management: There are relatively few fungicides effective against oomycetous fungi and control can be very difficult. Since most of the fungicides are fungistatic (inhibit the fungal growth) rather than fungicidal (kill the fungus) against P. mesembryanthemi, fungicidal treatments only suppress the fungus, but systemic infections cannot be cured. Downy mildew fungi evolve very quickly to form new races and can rapidly develop fungicide resistance. (Is this sentence necessary? It is scary.)
Good cultural practices and sanitation can prevent or minimize downy mildew of ice plants. Some management options include:
- Prune plants regularly and remove weeds to improve air circulation and reduce fungal growth.
- Avoid overhead irrigation during cool weather.
- Consider watering in the morning hours so that plants dry during the day.
- Do not over- or under-fertilize as it may increase the chances of infection.
- Monitor highly susceptible species like the red apple ice plant and remove and destroy plants with symptoms of infection.
- Consider other host plants as groundcovers when replacing diseased ice plants.
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References:
Chitambar, J. 2016. Peronospora mesembryanthemi. (http://blogs.cdfa.ca.gov/Section3162/?tag=peronospora-mesembryanthemi)
Francis, S. and G. Waterhouse. 1988. List of Peronosporaceae reported from the British Isles. Trans. Brit. Mycol. Soc. 91: 1-62.
McKenzie, E.H.C. and J. M. Dingley. 1996. New plant disease records in New Zealand: miscellaneous fungal pathogens III. New Zealand J. Bot. 34: 263-272.
Verwoerd, L. 1924. Peronospora mesembryanthemi n. sp., die oorsaak van ‘n donsige skimmelsiekte van Mesembryanthemum-soorte. Ann. Univ. Stellenbosch 2A: 13-23.
