Biology  |  |  Impacts  |  Detection  |  Management

 

Origin and Spread

The spotted lanternfly, Lycorma delicatula, is an invasive species to the United States, first discovered in Pennsylvania in 2014. It was originally from China and southern Asian countries such as India. It is likely to become a serious agricultural pest without natural enemies to keep populations low. It was accidentally introduced into South Korea in 2006 and has spread dramatically to become a major agricultural pest, especially for grape production.

The risk of spread in the northern US was once believed to be low due to cold winters. More recently, however, many eggs and newly hatched nymphs have survived the winter. While not yet in New York, the spotted lanternfly is on the border with Pennsylvania and if it does move into NY and become established, it has the potential to become a significant agricultural pest causing untold physical and economic damage.

Biology

Spotted lanternfly eggs hatch as nymphs in April and May during the early hours of the day. The black bodied nymphs go through 4 growth phases (instars) before becoming a winged adult. Instars 1-3 have white spotted black bodies, while the 4^th instar develops black and red mottling under the white spots. Adult lanternflies have grayish forewings with black spots; the hind wings are red and black spotted on the lower portion and grey and black with a bold white stripe on the upper portion. Adult females are about an inch in length; males are about 4/5ths of an inch. Adults are strong hoppers but weak fliers. In the fall, adults often shift to feeding the invasive Tree of Heaven (Ailanthus altissima). In late September until early winter, adults lay oothecas, or egg sacs, which house up to 30-50 brown seedlike eggs with a shiny, light orange/brown waxy coating. The egg sacs have a smooth, shiny surface. While lanternflies often lay eggs on Tree of Heaven, they will use any smooth, vertical surface including other smooth-barked trees, stones, vehicles, outdoor furniture and other manmade surfaces.  Eggs in Pennsylvania overwintered successfully in 2014; once eggs hatch the waxy coating is removed, leaving parallel lines of hatched egg sacs behind.

     

Impacts 

Both adults and nymphs use their piercing and sucking mouthparts to eat the phloem tissue of a wide variety of plants in order to obtain nutrients.  The insects also excrete a sugary fluid similar to aphid honeydew, which encourages mold and disease growth.  In the native range of the spotted lanternfly, these impacts does not normally kill host plants; absence of  natural predators, however, can lead to overinfestaton and cause sickness and death in infested plants. Overfeeding by the lanternflies can extract a damaging percentage of the plant’s nutrients, and the dripping sap from lanternfly feeding wounds combined with sugary lanternfly excretia can lead to mold and disease damage.

Spotted lanternflies feed on over 65 species of plants, preferring plants that have high sugar content and toxic metabolites. These include many agricultural species such as fruit vines (grapes), fruit trees (apples, cherries, peaches, pears, plums) and maple trees. Ornamental plants and forestry species including dogwoods, lilacs and pines are also susceptible. The spotted lanternfly has the potential to become a serious agricultural pest and stressor on natural systems.

Detection

In the spring, look for the white-spotted black-bodied nymphs and white-spotted, mottled red-and-black fourth instar nymphs feeding on any of the wide variety of host species, both woody and non-woody.  In the summer, adults are visible while feeding. Indicators of lanternfly damage are seeping sap wounds on non-woody and woody species, and patches of blackened soil around the plant base.  Other insects and molds are also attracted by the sugary secretions caused by the sap and honey dew, including ants, bees and wasps. In the fall, brownish egg sacs can be seen plastered to tree trunks (especially Tree of Heaven) or other smooth surfaces such as stones, vehicles, farm equipment or outdoor furniture.

Management

Spotted lanternfly management will vary based on whether the insect is found inside or outside existing quarantine areas.  To date, several towns in Pennsylvania including District, Earl, Hereford, Pike, Rockland and Washington and the boroughs of Bally and Bechtelsville are under quarantine. Quarantine areas may expand if the spotted lanternfly is found elsewhere in the US.

Within quarantine areas:

Egg sacs should be scraped off the host surface, soaked in alcohol or hand sanitizer and thrown away.

Background | Habitat | Origin | Introduction and Spread | Impacts | Identification | Prevention | Control | Occurrences | New York Distribution Map

Background

The spotted wing drosophila (SWD), Drosophila suzukii, is an invasive vinegar fly. The fly is small (about 2-3mm in size) with a pale body and bright red eyes. Male SWD have a black spot near their wingtip and black bands on their front legs, which may help to distinguish them from other look-alike vinegar flies. This species of fly was first observed in the United States in California in 2008; it was found in New England in 2011. SWD lay their eggs in ripe or ripening fruit and berries. When the larvae hatch, they consume the fruit leaving it deformed. Hannah 

Habitat

SWD affects many fruit and berries, including cherries, peaches, plums, pears, apples, raspberries, blackberries, strawberries, grapes, blueberries, and tomatoes. The insect also can infest non-commercial hosts such as crabapple, autumn olive, Japanese yew, beach plum, and wild rose. It not only infects already ripened fruit, but can affect fruit in the earlier stages of development as well. SWD are seen more in moderate climates and prefer the early summer or fall when temperatures are cooler (approximately 68° F). Adults will hibernate when temperatures drop to 40°F. In freezing temperatures, the larvae usually cannot survive.

Origin

Spotted wing drosophila are native to Southeast Asia.

Introduction and Spread

Various fruit crops will develop and ripen at different times throughout the growing season. The SWD will take advantage of this and move from one crop to another as the season progresses. Additionally, infested fruit may be shipped from different parts of the country and sold at markets, which increases the spread of SWD. This insect has a high reproductive rate. Within one year, the SWD can complete at least 15 generations. During the 2-9 weeks time frame that adults live, a female can lay 100-600 eggs in fruit.

Impact

When female SWD lay their eggs on the fruit, a small, barely visible scar is left on the fruit’s surface. Within a couple hours or a few days the larvae may begin to hatch and feed on the fruit from the inside, which eventually causes the fruit to collapse and look deformed. Fruit may start looking misshapen within 2-13 days after becoming infested. Secondary pests, such as molds and bacteria, may also further infect the fruit, exacerbating the damage.  Since SWD look very similar to other common vinegar flies, many populations of SWD go unnoticed and untreated until a large infestation occurs.

In 2009, yield loss from SWD was estimated to be in a range from zero up to 80% (Walsh et al. 2011). SWD is a big concern in areas located on the western coast of the United States, such as California, Oregon, and Washington. There, a large proportion of the nation’s commercial production of raspberry, blackberry, cherry, strawberry, and blueberry occurs. In the Northeast, SWD has affected raspberry and blackberry the most. Peaches and grapes are also affected in the Northeast. It is still unknown how this species will overwinter and if earlier season crops are of greater risk to be infested in the future (Demchak et al. 2012).

Identification

SWD is about 2-3 mm in size, with bright red eyes. The majority of the insect’s body is a pale brown with black horizontal stripes on the abdomen region. You can distinguish a male SWD from other vinegar flies in the Drosophila genus by a dark spot along the front edge of the wing near the wingtip. This spot may be missing on some SWD males, but another defining characteristic for males is the presence of two black bands on each front leg. Female SWD tend to have a saw-like ovipositor, larger than that of other species. Otherwise they look very similar to common vinegar flies. The white larvae of SWD are small and cylinder-shaped.

Prevention

Growers of fruits that are commonly affected by SWD are encouraged to inspect their crops frequently. Screens or growing inside a greenhouse have been used for individual plant protection to exclude the flies in some cases. However, this method may not be as suitable or practical for many growers and producers. Bait traps or lures to detect fruit flies may also be utilized to monitor the presence of SWD. Since females have fewer distinguishing characteristics than males, it is recommended to monitor the male populations to avoid confusion with other species. Traps should be placed in a field right before the fruit starts to turn color. For more information on making your own traps and placement of traps, refer to the Pennsylvania State University monitoring fact sheet, (Demchak et al. 2012).

Control

To control already-established infestations of SWD, remove all ripe and cull fruit when harvesting. Also, try to pick the fruit as soon as possible and do not leave harvested fruit exposed for long periods of time. Any fruit that has become infested should be promptly removed and disposed of properly. All damaged fruit should be buried, covered with plastic, or disposed of in a closed container. Leaving the infested fruit to decompose in the field where they dropped will give eggs and larvae still present on the fruit a chance to fully develop into mature insects causing the population on SWD to increase.

There are some biological control agents, such as parasitoids that affect species within the Drosophila genus (Dubuffett et al. 2009). Researchers at Oregon State University are exploring biological control methods specifically for SWD. However, it is still unknown if these predators are a reliable biocontrol method at this time.  Some pesticides that are approved may be applied across fields for SWD control. These treatments may need to be reapplied almost every 1-2 weeks. Three groups of pesticides, the pyrethroids, spinosyns, and organophosphates have been found to be effective. Since SWD has such a high reproductive rate, with multiple generations per year, it is suggested to use a variety of pesticides to reduce chemical resistance evolving within this species (Demchak et al. 2012). Contact your local Cornell Cooperative Extension office for more information on pesticides before use and always follow the directions on the label.

Occurrences

SWD has been documented in Japan, China, Korea, Thailand, India, Spain, and Hawaii. SWD was first observed in California in 2008.  In 2011, SWD was found in the Northeast in Pennsylvania.

New York Distribution Map

This map shows confirmed observations (green points) submitted to the NYS Invasive Species Database. Absence of data does not necessarily mean absence of the species at that site, but that it has not been reported there. For more information, please visit iMapInvasives.