- Author: Cheryl Reynolds
Spider mites, fruit moth and twig borer larvae, aphids, and bark cankers are just a few pests that can wreak havoc on stone fruit trees. With spring well underway and trees in full bloom and beginning to develop fruit, it's time to monitor and take action before these pests get out of hand.
UC IPM teamed up with UC farm advisors to develop a series of how-to videos that can help growers and pest control advisers monitor for pests and damage and determine if and when treatment is needed.
In one video, Sacramento Area IPM Advisor Emily Symmes gives a brief overview of how to monitor for webspinning spider mites. Spider mites build up in stone fruit trees as the weather warms up. Late spring through summer is the ideal time to monitor for mites and their damage, which includes leaf stippling and webbing. If mites build up too much, leaves can drop, fruit may not fully develop, and branches and fruit can be exposed to sunburn.
Shoot strikes, or dead drooping leaf tips, are often seen on young peach and nectarine trees. In a second video, UC Sutter and Yuba County Farm Advisor Janine Hasey explains how to monitor for shoot strikes and how to distinguish the culprits, oriental fruit moth and peach twig borer. Although Oriental fruit moth and peach twig borer can bore into both foliage and fruit, they cause the most devastating damage by feeding on fruit. Early season monitoring and treatment can prevent future fruit loss.
In plum and prune orchards, leaf curl aphids and mealy plum aphids cause leaves to curl and become distorted. Aphids produce honeydew, which can lead to the development of sooty mold, causing fruit to crack and blacken. Aphids are often present when leaves start to grow. In his video, Rick Buchner, UC farm advisor for Tehama County, discusses how to monitor for aphids and explains how to decide when treatment is warranted.
In a final video, UC Sacramento County Farm Advisor Chuck Ingels teaches how to distinguish Phytophthora root and crown rot from bacterial canker. The two diseases are often confused because they both cause bark cankers. Phytophthora root and crown rot is confined to the lower trunk, but when a bacterial canker infection occurs in the tree trunk, the diseases can often be confused. Bacterial canker can be confirmed by cutting away the outer bark and looking for characteristic red flecks on the inner bark. Correct identification of these diseases will help in choosing a management strategy.
- Author: Surendra K. Dara
Adult spotted lanternfly (Lycorma delicatula). Source http://hojae.net/520.
The Pennsylvania Department of Agriculture recently reported the first detection of yet another invasive hemipteran pest in the US. While efforts to have a good grip over other invasive hemipterans like the Asian citrus psyllid, the Bagrada bug, and the brown marmorated stink bug is still underway, there is a new pest that could potentially impact industries ranging from lumber to wine.
An exotic pest known as the spotted lanternfly, Lycorma delicatula (White) was recently detected in Berks County, PA. Spotted lanternfly, which is actually not a fly, but a planthopper is also referred to as “spot clothing wax cicada” or “Chinese blistering cicada” in the literature. It belongs to the family Fulgoridae in the order Hemiptera. Fulgorids or members of the family Fulgoridae are moderate to large planthoppers generally referred to as lanternflies because of the inflated front portion of the head that was thought to be luminous. Spotted lanternfly is regarded as a poisonous insect in Chinese medicine and used for relief from swelling.
Origin and distribution
Spotted lanternfly is native to China and is present in Southeast Asia. It was first reported in South Korea in 2006 and rapidly spread to different parts of the country.
Spotted lanternfly feeds on a variety of host plants including fruit trees, ornamental trees, woody trees, and vines. Apples, birch, cherry, dogwood, grapes, Korean Evodia, lilac, maple, poplar, stone fruits, and tree-of-heaven are among more than 70 species of hosts attacked by this pest. Tree-of-heaven, which contains high concentrations of cytotoxic alkaloids, is one of the favorite hosts. This is probably why spotted lanternfly is considered poisonous and used in traditional Chinese medicine. Other preferred hosts such as Korean Evodia (Bebe tree) are also used in oriental medicine suggesting that spotted lanternfly has a high preference for hosts that contain toxic secondary metabolites. Observations in South Korea also indicate that spotted lanternfly appears to have a wider host range early in life as young nymphs and a narrow range as they grow older, especially before egg laying. Choosing plants with toxic metabolites for egg laying is thought to be a mechanism of defense to protect from natural enemies. Although grape vine does not have toxic metabolites like these other hosts, spotted lanternfly showed a strong preference in studies conducted in South Korea. Sugar content of the host plant also appears to play a role in their choice with a preference for hosts containing high sucrose and fructose content.
Eggs are laid on tree trunks in ootheca (egg case) in groups of 30-50 and are covered in a yellowish brown waxy deposit. Eggs usually hatch during the early hours of the day. Waxy deposit disappears on old egg masses which look like brown seeds. There are four nymphal instars. Nymphs have a black body. The first three instars have white spots while the fourth instar has red wing pads and upper body. Nymphs start climbing up the trees after they emerge and fall off when there is a physical obstacle or disturbance from wind or other factors and start climbing up again. This falling and ascending cycle is thought to be a means of host selection and dispersal. Adult males are 20.5-22 mm (0.81-0.87 inches) long from head to the end of the folded wing and females are 24-26.5 mm (0.94-1.04 inches) long. Forewings are greyish with black spots in different patterns. Part of the hind wing is red with black spots and the rest is white and black. Tips of the wings show a network of veins (reticulated). Abdomen is yellowish with black bands. Legs are black and have white spots during nymphal stages. Length of the legs varies from 15-18 mm (0.59-0.71 inches) in adult males and 18-22 mm (0.71-0.87 inches) in adult females. Adults are weak flyers, but good hoppers. Head is black with piercing and sucking mouthparts. Life cycle is typically univoltine (one generation per year) and spotted lanternfly overwinters as eggs.
Adults and nymphs feed on phloem tissues of foliage and young stems with their piercing and sucking mouthparts and excrete large quantities of liquid. Due to the sugar content of the liquid, plant parts covered with spotted lanternfly excretion harbor mold growth, which could hinder plant growth or even cause death.
Neonicotinoids, pyrethrins, and organophosphates are among the chemical insecticides effective against spotted lanternfly. Adults and 2nd-4th instar nymphs appear to be attracted to spearmint oil which could be used in their control. Using sticky traps at the base of the tree trunks also appears to be a good management strategy. Parasitic wasp, Anastatus orientalis is reported to parasitize up to 69% of spotted lanternfly eggs in China. This egg parasitoid is considered a potential biocontrol agent for release against the spotted lanternfly in South Korea.
Photos of the pest
Pictures of the spotted lanternfly can be found at the following sources:
Fourth instar nymph: https://www.flickr.com/photos/itchydogimages/6984394006/in/pool-lanternbugs
Early instar nymphs: https://www.flickr.com/photos/itchydogimages/6197213287/
Barringer, L. 2014. Pest alert: Spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae). Pennsylvania Department of Agriculture.
Choi, M.-Y., Z.-Q. Yang, X.-Y. Wang, Y.-L. Tang, Z.-R. Hou. 2014. Parasitism rate of egg parasitoid Anastatus orientalis (Hymenoptera: Eupelmidae) on Lycorma delicatula (Hemiptera: Fulgoridae) in China. Korean J. Appl. Entomol. 53: 135-139.
Ding J., Y. Wu, H. Zheng, W. Fu, R. Reardon, and M. Liu. 2006. Assessing potential biological
control of the invasive plant, tree-of-heaven, Ailanthus altissima. Biocontrol Sci. Technol. 16:547-566
Han, J. M., H. Kim, E. J. Lim, S. Lee, Y.-J. Kwon, and S. Cho. 2008. Lycorma delicatula (Hemiptera: Auchenorrhyncha: Fulgoridae: Aphaeninae) finally, but suddenly arrived in Korea. Entomol. Res. 38: 281-286.
Kim, J. G., E.-H. Lee, Y.-M. Seo, and N.-Y. Kim. 2011. Cyclic behavior of Lycorma delicatula (Insecta: Hemiptera: Fulgoridae) on host plants. J. Insect Behav. 24: 423-435.
Frantsevich L., A. Ji, Z. Dai, J. Wang, L. Frantsevich, and S. N. Gorb. 2008. Adhesive properties of the arolium of a lantern-fly, Lycorma delicatula (Auchenorrhyncha, Fulgoridae). J. Insect Physiol 54: 818– 827.
Lee, J.-E., S.-R. Moon, H.-G. Ahn, S.-R. Cho, J.-O. Yang, C. Yoon, and G.-H. Kim. 2009. Feeding behavior of Lycorma delicatula (Hemiptera: Fulgoridae) and response on feeding stimulants of some plants. Korean J. Appl. Entomol. 48: 467-477
Moon. S.-R., S.-R. Cho, J.-W. Jeong, Y.-H. Shin, J.-O. Yang, K.-S. Ahn, C. Yoon, and G.H. Kim. 2011. Attraction response of spot clothing wax cicada, Lycorma delicatula (Hemiptera: Fulgoridae) to spearmint oil. Korean Soc. Appl. Biol. Chem. 54: 558-567./span>
- Author: Ria DeBiase
Nursery workers are our first line of defense in detecting light brown apple moth when growing ornamental plants in commercial nurseries. A new brochure and video can help those in the field distinguish light brown apple moth from several look-alike caterpillars.
Light brown apple moth is currently under a California Department of Food and Agriculture quarantine that regulates the interstate shipment of plants to keep the moth from spreading to new areas. It has been quarantined in various counties throughout coastal California ranging from Mendocino to San Diego.
Correct field identification of the light brown apple moth is the first step in containing the spread of this moth. Unfortunately several other leafroller caterpillars, including the orange tortrix, omnivorous leafroller, avocado leafroller, and apple pandemic moth, look similar to light brown apple moth caterpillars. This makes photo identification tools that can go into the field with workers, like the Field Identification Guide for Light Brown Apple Moth in California Nurseries, a useful resource for nursery workers.
The field guide was created by Steven Tjosvold, Neal Murray, University of California Cooperative Extension; Marc Epstein, Obediah Sage, California Department of Food and Agriculture; and Todd Gilligan, Colorado State University with the Statewide Integrated Pest Management Program (UC IPM).
An exotic and invasive pest from Australia, light brown apple moth has a host range of more than two thousand plants. It is a pest to a wide range of ornamental and agricultural crops, including caneberries, strawberries, citrus, stone fruit, apples, and grapes. The caterpillars eat leaves and buds, leading to weak or disfigured plants. They also can feed directly on fruit, causing the fruit to be unmarketable.
For more information on light brown apple moth and other leafrollers found in nurseries, see the UC Pest Management Guidelines for Floriculture and Nurseries.
- Author: Cheryl Reynolds
It's cherry growing season and a good time to begin looking for spotted wing drosophila (SWD), Drosophila suzukii. SWD is a small fruit fly that attacks soft-flesh fruit such as cherry, blueberry, raspberry, and blackberry. It first appeared in 2010, and its damage to fruit and increased management costs led to significant economic losses to cherry growers throughout California and the Pacific Northwest.
Unlike other fruit flies that infest rotted fruit, SWD attacks undamaged fruit. As cherry fruit begins to develop and starts to change color from light green to straw, SWD lays its eggs just under the skin of fruit, creating a small scar or a “sting.” One to three larvae may develop inside each cherry, feeding on the fruit and causing it to become brown and soft. Many times SWD flies are not noticed until fruit is mature, and by that time management is not very effective.
Prevention is the key, and one way to prevent damage is to monitor for the pest when it first becomes active. SWD can be monitored with several types of traps partly filled with apple cider vinegar to lure the pest. Monitor traps weekly through the end of harvest, and be sure to confirm the presence of SWD, as other Drosophila spp. may be present in trap catches. SWD males have a single dark spot on the tip of its wing and females have a large ovipositor. See the UC IPM Pest Management Guidelines for identification help and a dichotomous key.
Spotted wing drosophila is still a relatively new pest, and management information continues to change. UCCE Entomology Advisor David Haviland and other researchers have been working to provide what help they can. Haviland has designed a bucket trap called the “Haviland trap” and is working with others to field-test experimental lures for SWD. He's also studying a possible biological control agent. Research has led to new grower guidelines so that early season cherries can be produced and sold internationally. Check out the 2014 Recommendations for Sweet Cherry (PDF).
For management in backyard cherries or other urban areas, see the SWD Pest Note.
For more information about UC IPM's recent work, see the 2013 Annual Report.
- Author: Surendra Dara
An Asian citrus psyllid (ACP) was found on a trap in southern Arroyo Grande last week (identification was made by CDFA on 26 March, 2014). This is the first discovery of this invasive pest in San Luis Obispo County. After its first detection in California in August, 2008, ACP was found in January, 2011 in Ventura County, 7 November, 2012 in Santa Maria, and March, 2014 in San Luis Obispo County.
CDFA will be working with Ag Commissioner in establishing a quarantine area and other actions to handle the situation.
ACP is an invasive pest that transmits a devastating bacterial disease, huanglongbing (HLB) or citrus greening or yellow dragon disease threatening the California citrus industry. It is estimated that each year California spends more than $3 billion to handle exotic and invasive pest, disease, and weed problems. Exotic and invasive organisms are native to other areas or countries which are inadvertently brought to California and cause a major concern.
HLB infection was found in a tree in Hacienda Heights a couple of years ago, where more than 20 infected twigs brought from another country were grafted to a backyard citrus tree. This was detected by CDFA and the tree was immediately destroyed. It is important for general public to be aware of the risk and refrain from bringing in plant material without a quarantine permit.
Below is a short animated video made by Ellen Schofield and David Andow of the University of Minnesota that explains how invasive species become a problem in an introduced area.
Management options for growers and homeowners can be seen at http://ucanr.edu/sites/ACP/.
USDA ARS researchers in Fort Pierce, FL found out that exposing potted citrus plants for at least 48 hours to 104-107 oF reduced or eliminated HLB infection. Additional details of this study can be read at http://www.ars.usda.gov/is/pr/2013/130805.htm.
My previous blog (http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=4165) about this pest gives an overview of the pest biology and control.
Current distribution of ACP, HLB, and the parasitic wasps of ACP in California can be seen at http://ucanr.edu/sites/ACP/Distribution_of_ACP_in_California/.
Growers and homeowners with questions about ACP or HLB can contact local UCCE or Ag Commissioner offices. Citrus growers in Santa Barbara or San Luis Obispo Counties can also contact Cressida Silvers, ACP/HLB Grower Liaison of Citrus Pest and Disease Prevention Program at firstname.lastname@example.org or 805-284-3310 for additional information./span>