- Posted By: Surendra Dara
- Written by: Surendra Dara
Life stages of the European pepper moth, Duponchelia fovealis. Eggs (top left, photo credit: Lance Osborne, University of Florida), larva (top middle, photo credit: Bryan Vander Mey, UCCE), pupa in an opened cocoon (top right, photo credit: James Hayden, Florida Department of Agriculture and Consumer Services, Division of Plant Industry) and adult male (left) and female (right) moths (bottom, photo credit: James Hayden)
European pepper moth (EPM), Duponchelia fovealis Zeller is an invasive pest in the US. It was first discovered in San Diego County in 2004 and again in July, 2010. EPM has a CDFA pest rating of C, which means it is currently widespread in California. APHIS, National Plant Board, and industry stakeholders have established an EPM task force to address the pest issue. I have been invited to be a part of the Technical Working Group along with my UCCE colleagues, James Bethke and Steve Tjosvold to work on research and outreach related to this pest. Information on the economic impact of this pest in California or in the US is unknown, but here is some general information about this pest.
EPM belongs to the family Crambidae. Crambids are known as grass moths or close-wing moths. Older literature classifies this pest under the family Pyralidae. Some sources also refer to EPM as southern European marshland pyralid. Peppered moth, Biston betularia (Common name: measuringworms, Family: Geometridae, Order: Lepidoptera) from Europe is not related to this species. It can be confusing when the name European peppered moth also appears in some sources, but verifying the scientific name helps confirm the identity.
Origin and Distribution: EPM is a pest native to the Mediterranean region and the Canary Islands. It is also reported to be an important greenhouse pest in the Netherlands for the past two decades. It is an established pest in many European countries, the Middle East and Africa. EPM is now reported to be present in several central and southern California counties and in Arizona, Colorado, Oklahoma, Texas, Georgia and Florida. EPM was also reported in a southern Ontario, Canada greenhouse in 2005.
Host range: EPM is a polyphagous pest and has a very wide host range that includes several crop plants like corn, peppers, tomatoes, squash, and strawberries and ornamental plants like azalea, begonia, geranium, and poinsettia. Due to its feeding behavior and preference to infest foliage and plant parts near or below the soil line, crops that have such plant structure may be more vulnerable to this pest.
Biology: Eggs are oval, 0.5-0.7 mm long, whitish-green initially and turn bright red as they mature. Females can lay up to 200 eggs either individually or in batches of 3-10 in a roof-tile pattern. Larvae are creamy white to brown with dark spots on their body and have a dark head capsule. They measure up to 20-30 mm when they are fully developed. Pupa is 9-12 mm long, yellowish to light brown initially and turn dark with maturity. A cocoon is spun around the pupa with silk, frass, and soil particles under the foliage, below the soil line or attached to the pots. Adults have brown to grey wings with a wing span of about 20 mm. Adults are good fliers. Males have a long, slender abdomen that is turned upwards. Length of the life cycle depends on temperature, but varies from 6-8 weeks. Egg stage lasts for 4-9 days, larval stage for 3-4 weeks, pupal stage for 1-2 weeks, and adult stage for 1-2 weeks. They produce multiple generations especially in greenhouses (up to 8 to 9) or in warm areas such as California and southeastern US. They can be limited to greenhouses in cooler regions or during cooler seasons of the year and seen in the fields under ideal conditions.
Mature European pepper moth larva in the potting soil below the surface
(Photo credit: Lyle Buss, University of Florida)
Damage: EPM larvae feed on roots, stems, foliage, inflorescences and fruits. They can also feed on the organic matter in the soil. Although they have a preference for feeding at the plant base, damage can be inflicted higher in the plant. Sometimes, larvae emerging from the eggs laid on the top of the foliage can burrow their way down through the stem. Damage ranges from holes in the foliage, wilting, defoliation, girdling of the stem to stem collapse. Damaged areas are also exposed to fungal diseases like Botrytis. Larvae prefer moist conditions and hide under the foliage that is in contact with soil, just below the soil line or in the tunnels formed by spinning the leaves together. In potted plants where the foliage is not in contact with the soil, larvae can be found in webbing near the edges of the pots.
Stem girdling of peppers by larval feeding of the European pepper moth. Photo credit: Bryan Vander Mey, UCCE.
Management: Sanitation to remove debris and infestation sites like lower leaves in contact with the soil and use of drier potting medium appear to help reduce the infestation. Biological control with Bacillus thuringiensis, predatory mites (Stratiolaelaps miles, Hypoaspis miles and H. aculeifer), predatory beetle (Dalotia coriaria), parasitoid wasps (Trichogramma evanescens and T. cacoeciae), and entomopathogenic nematodes (Heterorhabditis bacteriophora and Steinernema sp.) are reported to be effective. Chemical control can be difficult with contact insecticides as the larvae hide in protected areas. However, control with acephate, azadirachtin, chlorpyrifos, emamectin, imidacloprid, pyrethrins, and spinosad was found to be effective in areas where they are registered to be used.
What to do: If you notice EPM damage on your crop, please contact me at skdara@ucdavis.edu or 805-781-5940.
Additional details about EPM and more photos can be found at the below sources.
http://ucanr.edu/articlefeedback
References:
Bethke, J. and B. Vander Mey. 2010. Duponchelia fovealis. Pest Alert, University of California Cooperative Extension, San Diego.
Brambila, J. and I. Stocks. 2010. The European pepper moth, Duponchelia fovealis Zeller (Lepidoptera: Crambidae), a Mediterranean pest moth discovered in central Florida. Pest Alert, Florida Department of Agriculture and Consumer Services, Division of Plant Industry.
Messelink, G. and W. Van Wensveen. 2003. Biocontrol of Duponchelia fovealis (Lepidoptera: Pyralidae) with soil-dwelling predators in potted plants. Comm. Appl. Biol. Sci., Ghent University 68: 159-165.
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1000&context=systentomologyusda
http://entnemdept.ufl.edu/creatures/veg/leps/european_pepper_moth.htm
http://mrec.ifas.ufl.edu/lso/dupon/dupon.html
http://nationalplantboard.org/docs/spro/spro_duponchelia_2011_08_05.pdf
http://www.freshfromflorida.com/pi/pest_alerts/pdf/duponchelia_fovealis.pdf
/span>- Posted By: Surendra Dara
- Written by: Surendra Dara
Spotted snake millipede infestation on zucchini (Photo by: Surendra Dara)
Phylum: Arthropoda
Subphylum: Atelocerata
Class: Diplopoda
Order: Julida
Family: Blaniulidae
Scientific name: Blaniulus guttulatus (Bosc, 1792)
The snake like slender body and brownish or pinkish spots on the lateral sides give them the name spotted snake millipede (SSM). SSM are soil inhabitants that feed on decaying plant material. When disturbed, they curl into a coil.
Biology: They are about 15 mm long and have approximately 60 body segments. Eggs are deposited in the soil. Juveniles have three pairs of legs. Number of body segments increases with each molt and it takes about a year to reach adult stage.
Feeding of millipedes on the root system causes plant collapse and death. See the root system completely disconnected from the plant. (Photo by: Surendra Dara)
Damage: Although they primarily feed on decomposing organic matter, they can become serious pests of cultivated crops in certain conditions. They are capable of causing both primary and secondary damage. During prolonged dry conditions SSM can be attracted to the crop plants for their moisture needs. Damage to the plant tissue due to other pests and diseases can also attract SSM. Infestation is severe in soils rich in organic matter. Rainfall can also activate their infestation.
Strawberries, potatoes, sugar beets, turnips, beans, squash and other vegetables are susceptible to SSM infestation. Feeding damage to the root system can cause rapid death of the plant.
Zucchini field in San Luis Obispo with severe spotted snake millipede infestation. Crop loss can be seen in large parts of the field. (Photo by: Surendra Dara)
Management: Proper disposal of crop residue, avoiding fields with decaying plant material, removal of old mulch or decomposing leaves can minimize the chances of infestation. Proper water management will also reduce the attractiveness of soil for SSM infestation. Reports indicate mixed results with various chemicals, but certain thiocarbamate, carbamate, organophosphate, neonicotinoid, and pyrethroid chemicals were found effective. Entomopathogenic nematodes like Steinernema feltiae are also effective in managing SSM.
- Posted By: Surendra Dara
- Written by: Surendra Dara and Brian Cabrera
Two species of dipteran larva (maggots) were found feeding on strawberry fruits in the Santa Maria area recently. Last year, there was a minor issue of fungus gnat larvae and another species (probably Delia sp.) damaging young strawberry plants, but the recent observations are isolated incidents of damage to the fruit. Specimens brought to the Santa Barbara Ag Commissioner's office were identified by the county entomologist, Dr. Brian Cabrera.
Strawberries from a greenhouse in the Santa Maria area were infested with dark-winged fungus gnat larvae (Family: Sciaridae). These maggots have a dark head capsule and a worm-like body.
Dark-winged fungus gnat larva feeding on a strawberry (above). Larvae have dark, shiny head capsule with a whitish, slender, worm-like body (below). Photos by: Brian Cabrera
The second incident was where some field strawberries were heavily infested with the larvae of the fruit fly, Drosophila simulans Sturtevant. It is a species very closely related to the common fruit fly, D. melanogaster. Both fruit fly species are very similar, but can be distinguished based on the characters of external male genitalia.
Fruit fly, Drosophila simulans larva in damaged strawberry (above) and adult female (below). Photo by: Brian Cabrera
Fungus gnats or fruit flies are normally not considered as pests of strawberries. Ripe fruit left on the plants could have attracted resulting in the damage we noticed. With good sanitation practices and timely harvesting, these insects are not expected to damage strawberry fruits.
http://ucanr.edu/articlefeedback
Reference:
Sturtevant, A. H. 1920. Genetic studies on Drosophila simulans. I. Introduction. Hybrids with Drosophila melanogaster. Genetics 5: 488-500. (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1200491/pdf/488.pdf)
- Posted By: Surendra Dara
- Written by: Surendra Dara
Light brown apple moth (LBAM), Epiphyas postvittana (Walker) was recently found in Santa Barbara County for the sixth time. LBAM is a quarantine pest on the United States mainland and can cause serious damage to various crops, nurseries, fruit trees, landscapes, and native plants.
Light brown apple moth (Epiphyas postvittana) male (above, from California Agriculture 2008, vol 62: 57-61) and female (below, photo by Jack Kelly Clark).
Origin and distribution: It is an invasive pest native of Australia, but has been present in Hawaii for more than a century. It was first found in Alameda County in 2007. It is now frequently found in Alameda, Contra Costa, Marin, Monterey, Napa, San Benito, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano, and Sonoma counties in California. It has also been detected in San Diego, San Luis Obispo, and Santa Barbara counties.
Host range: LBAM feeds on a variety of host plants, but prefers members of Asteraceae (aster), Fabaceae (legumes), Polygonaceae (knot-weed) and Rosaceae (rose). It is a pest of apples, apricots, peaches, pear, grapes, strawberries, cane berries, cole crops, ornamental shrubs, trees and many other hosts. Nurseries near urban areas are especially sensitive to LBAM infestation in California. If it spreads and establishes as a pest, many agricultural crops can be at risk.
Damage: Damage to foliage and other parts by rolling and webbing, loss of inflorescence, feeding on or boring into the buds, fruit, or stems, fruit drop or damage to the surface, and exposing the damaged areas to plant pathogens typical of LBAM larval feeding.
Light brown apple moth larva and damage to the foliage. You can also see the silken webbing that attaches the leaves together. Photo by Jack Kelly Clark.
Biology: LBAM belongs to a large lepidopteran family of Tortricidae. It is a large family containing many of the common months including important pests such as codling moth (Cydia pomonella), oriental fruit moth (Grapholitha molesta), spurce budworms (Choristoneura spp.), and the western black-headed budworm (Acleris gloverana). Mexican jumping-bean moth (Cydia deshaisiana) also belongs to this family. There are 1200 species of tortricids in North America.
Eggs deposited in batches and covered with transparent material. (From California Agriculture 2008, vol 62: 57-61)
LBAM eggs are laid in groups of 20-50 in overlapping manner and are covered with greenish transparent material. On average, females lay a total of 120-500 eggs in its life time. Eggs turn dark as they mature and hatch in 1-2 weeks. Larvae are pale to medium green with a yellowish to tan colored head capsule. Younger larvae roll the leaves and form webbings of leaves as they mature. Mature larvae may also bore into fruits. Mature larvae are about 10-18 mm long. During winter, larvae can survive for two months without feeding. Pupae are formed in a silken cocoon among the leaf webbings. They turn from green to brown as they mature in 1-3 weeks. Adults mate right after they emerge and females lay eggs within 2-3 days after emergence. Adults are small, light brown with darker markings and have a wing span of 16-25 mm. They hold their wings in a roof-like pattern at rest. Markings on their wings can be highly variable and identification based on external features can be very difficult. Positive identification of LBAM adults often requires examination of reproductive organs. Females are lighter colored and larger than males. They rest in sheltered parts of the plant canopy during the day time and fly during the night time. They are not powerful flyers, so stay close to the infested areas within a 100 m (330 feet) range. Adults survive for 2-3 weeks. Depending on temperature, there can be two (Central and Noth Coast areas) or three to four (Central Valley and Southern California) generations per year in California.
Female (A) and male (B-H) moths. Notice the variation in the wing pattern in males. Similarity of these moths to other tortricid moths makes it difficult to distinguish them based on external characters. (From California Agriculture 2008, vol 62: 57-61. Photos A and B by David Williams, State of Victoria Department of Primary Industries, C to H by Jack Kelly Clark)
LBAM eggs are laid in groups of 20-50 in overlapping manner and are covered with greenish transparent material. On average, females lay a total of 120-500 eggs in its life time. Eggs turn dark as they mature and hatch in 1-2 weeks. Larvae are pale to medium green with a yellowish to tan colored head capsule. Younger larvae roll the leaves and form webbings of leaves as they mature. Mature larvae may also bore into fruits. Mature larvae are about 10-18 mm long. During winter, larvae can survive for two months without feeding. Pupae are formed in a silken cocoon among the leaf webbings. They turn from green to brown as they mature in 1-3 weeks. Adults mate right after they emerge and females lay eggs within 2-3 days after emergence. Adults are small, light brown with darker markings and have a wing span of 16-25 mm. They hold their wings in a roof-like pattern at rest. Markings on their wings can be highly variable and identification based on external features can be very difficult. Positive identification of LBAM adults often requires examination of reproductive organs. Females are lighter colored and larger than males. They rest in sheltered parts of the plant canopy during the day time and fly during the night time. They are not powerful flyers, so stay close to the infested areas within a 100 m (330 feet) range. Adults survive for 2-3 weeks. Depending on temperature, there can be two (Central and Noth Coast areas) or three to four (Central Valley and Southern California) generations per year in California.
Management: Insecticides like insect growth regulators and spinosyns, biopesticides like Bacillus thuringiensis-based products, natural enemies that include predators and parasitoids are some management options. However, due to its current status in California, use of pheromone traps to cause mating disruption and quarantine practices to restrict movement are important components of current LBAM management. According to Guy Tingos, Deputy Ag Commissioner, Santa Barbara County, movement of nursery stock into Santa Barbara County from areas where LBAM is established must have a thorough inspection and LBAM certification to ensure the material is free of the pest. Movement of nursery stock, cut flowers, fruit or other plant material that can host LBAM out of quarantine area is highly regulated. Tingos also said that commercial farm operations in infested areas should be under compliance agreement for plant movement and public in quarantine areas should not move the host plants out of their property.
For insect identification and information on quarantine regulations contact your local Ag Commissioner's office.
Additional information can be found at the following sources:
CDFA website for photos, videos and other information: http://www.cdfa.ca.gov/plant/PDEP/lbam/lbam_main.html
National Invasive Species Information Center: http://www.invasivespeciesinfo.gov/animals/applemoth.shtml
UC IPM website: http://www.ipm.ucdavis.edu/PMG/r302303011.
http://ucanr.edu/articlefeedback
References:
Borror, D. J., C. A. Triplehorn, and N. F. Johnson. 1989. An introduction to the study of insects, 6th edition. Saunders College Publishing.
Varela L. G., M. W. Johnson, L. L. Strand, C. A. Wilen and C. Pickel. 2008. Light brown apple moth's arrival in California worries commodity groups. California Agric. 62: 57-61. (http://ucanr.org/repository/cao/landingpage.cfm?article=ca.v062n02p57&fulltext=yes)
/span>
- Author: Surendra K. Dara
Strawberry plants suffering from salt toxicity. Symptoms include brown and brittle leaf margins (above, photo by Albert Ulrich, UC) and stunted plant growth (below, photo by Stuart Styles, CalPoly).
Strawberry is among the crops that are very sensitive to salinity. In addition to the drip irrigation system that caters to the water needs throughout the crop season, overhead aluminum sprinklers are used during the first few weeks after transplantation to leach out salts from the root zone. Lack of rains earlier during this season has caused some concern about the impact of salinity on young strawberry plants. However, with the recent rains the total amount of precipitation in Santa Maria area for January, 2012 was about 2 inches (~50 mm) easing some of the concerns.
Symptoms of salt injury include dry and brown leaf margins, brittle leaves, stunted plant growth, dead roots and plants. When salt toxicity is seen in localized areas in a field, it could be due to poor drainage. Symptoms can be seen throughout the field when salinity of the irrigation water is high. Excessive fertilization or application to wet foliage can also result in salt toxicity. More than 0.2% of sodium or more than 0.5% of chloride in plant tissue indicate salt toxicity.
Salinity of the irrigation water depends on the amount of sodium, calcium and magnesium salts. Salinity is measured either as total dissolved solids (TDS) or the electrical conductivity (EC) imparted by the salts. The latter is often considered a better measure of salinity and is expressed as the EC of the irrigation water (ECw) or the EC of the saturated soil extract (ECe). Units of measurement for are milligrams/liter (mg/L) for TDS and decisiemens/meter (dS/m) for EC. Other parameters for soil salinity are pH and the sodium absorption ratio (SAR). SAR is a measurement of sodium absorption compared to calcium and magnesium absorption and is used as an infiltration index.
Insufficient leaching of irrigation water in the soil is a major cause of salt accumulation in the root zone. When irrigation is made just to meet the plant needs, salts gradually build up in the root zone. It is important to provide sufficient irrigation so that water will wash the salts away from the root zone. The proportion of water that leaches below the root zone after meeting the crop needs is known as leaching factor (LF). The amount and frequency of irrigation should be calculated appropriately to allow sufficient leaching at the same time avoiding excessive soil moisture which could cause other problems.
Compared to the crops grown in hot and dry areas, crops grown in milder climatic areas such as California Central Coast are likely to tolerate higher salinities. Salts in the Central Coast area waters are gypsiferous with calcium and sulfate ions. Waters with such salts do not cause the same level of detrimental effects compared to water with chloride even when they have same ECw.
According to Dr. Stuart Styles, Professor of BioResource and Ag Engineering at Cal Poly, ECw (salinity of the irrigation water) is a better indicator than ECe (salinity of the soil) to measure the impact of salinity on strawberry or other crop yields in the Central Coast. There can be up to a 50% reduction in the yield potential of strawberries when the salinity increases from 0.7 to 1.7 ECw (dS/M) with a leaching factor of 15-20%.
It is important to look at the type of salt and kind of test being done to determine the salinity. It is also necessary to consider the leaching factor when scheduling irrigation. Sampling the irrigation water two or more times a year to test is recommended if salinity is suspected. The following are ideal properties of irrigation water for strawberries:
Characteristic |
Ideal level |
Electrical conductivity (ECw) |
0.7 dS/m |
Total dissolved salts (TDS) |
450 mg/L |
Sodium |
3 SAR |
Chloride |
4 meq/L (milliequivalent/L) |
Boron |
0.7 mg/L |
Nitrate |
5 mg/L |
Bicarbonate |
1.5 meq/L |
Acidity |
6.5-8.5 pH |
http://ucanr.edu/articlefeedback
Reference:
Grattan, S. R. 2002. Irrigation water salinity and crop production. UCANR publication 8066 (http://anrcatalog.ucdavis.edu/pdf/8066.pdf)
Hanson, B. R. and W. Bendixen. 2004. Drip irrigation evaluated in Santa Maria Valley strawberries. California Agriculture 58:48-53 (http://ucanr.org/repository/cao/landingpage.cfm?article=ca.v058n01p48&fulltext=yes#bib5)
Maas, E. V. and S. R. Grattan. 1999. Crop yields as affected by salinity. In R. W. Skaggs and J. van Schilfgaarde, eds., Agricultural Drainage. Agron. Monograph 38. ASA, CSSA, SSSA, Madison, WI.
Martínez, M. C. and C. E. Alvarez. 1997. Toxicity symptoms and tolerance of strawberry to salinity in the irrigation water. Scientia Horticulturae 71: 177-188.
2008. IPM for strawberries. UCANR publication 3351.
/span>