- Author: Sonia Rios
Avocado growers have one more thing to worry about, just recently things have settled with the polyphagous shot hole borer and have recently had a wakeup call about the Redbay ambrosia beetle(Xyleborus glabratus)that carries the deadly fungus, Laurel wilt (Raffaelea lauricola). Now we have the invasive Spotted lantern fly (SLF)(Lycorma delicatula), to worry about. Originally from China, has spread to Korea and Japan, and has been found most recently in the United States in Pennsylvania in September 2014. The insect has now been found in New Jersey, Virginia and Delaware. These insects are pests of many agricultural crops including almonds, apples, blueberries, cherries, peaches, grapes and hops as well as hardwoods such as oak, walnut and our tasty avocados amongst other specialty crops. There is the potential for far reaching economic damage if the SLF becomes widely established in the United States and experts believe the lantern fly is likely to make its way to California soon. In 2019, California Department of Food and Agriculture (CDFA) inspectors have reported to date finding a total of 11 dead spotted lanternflies this year on cargo planes arriving at California airports in Sacramento, Stockton and Ontario when originally looking for Japanese beetles. The dead SLF specimens found on the cargo planes at California airports this summer and early fall were all adults. It is believed that they flew into the planes during loading activities at the airport in Allentown, PA and later died en route. The airport has since been treated to reduce and control SLF populations at the facility.
The name lanternfly can be misinforming; SLF have little in common with any type of fly. When looking at the adults with wings spread and can also make them look like moths. They are actually planthoppers in the order Hemiptera, or true bugs, and are closely related to brown marmorated stink bugs, aphids and leafhoppers. All insects in this order have piercing-sucking mouthparts which allow them to drill into the phloem of a plant to feed directly on the sweet sap and weaken the plant. From what is known in the current Pennsylvania infestations, SLF has shown to have one generation per year consisting of four nymphal stages, an adult stage, and overwintering as egg masses. Being true bugs, spotted lanternflies molt to progress between stages. Egg hatch is over an extended time period with the first instar nymphs appearing in May and June. Mating takes place starting in late August with egg-laying taking place in September through November or until the first killing freeze. It is unknown how exactly the life cycle would be in California, as the pests hasn't yet been found in California.
The first instar nymph is approximately ¼” long and black with white spots, and occasionally mistaken for a tick. Second and third instar nymphs are also black with white spots, but the fourth instar nymph takes on a red coloration with white spots and can be up to ¾”. Fourth instar nymphs molt and become adults approximately 1 inch in length. The adult SLF is about 2.5 cm (1 inch) in length. The fore wings are greyish-brown with black spots, with the wing tips having a darker, brick-and-mortar pattern. The hind wings are mainly red with black spots, followed by a white band and a black tip. When the spotted lanternfly is at rest, a hint of the red color can be observed through the forewings, but the color is especially noticeable when it is in flight. The body is mainly black, but the abdomen appears to be mostly yellow with black bands going down its length.
Signs and Symptoms
Spotted lanternfly causes damage to plants in two different ways. The nymphs and adults feed on plants using their piercing mouthparts to suck fluids from the stems or leaves. This has been shown to cause stunted growth, localized damage, reduced yields, and, in extreme cases, even death of the plant. Additionally, as the spotted lanternfly feeds, it excretes a sugary substance called honeydew. This honeydew, in addition to being attractive to ants, wasps, and other insects, is readily colonized by sooty mold, which can cause parts of the plants to become blackened, reducing photosynthesis and affecting the quality of the plants.
Source of threat
Spotted lanternflies have been documented to feed on over 70 species of trees and plants.Beware, the. SLF is a hitchhiker and are not shy.On their own, they are able to move 3 to 4 miles through walking, jumping and flying. However, can be spread long distances by people who move infested material or items containing egg masses. Egg masses, juveniles, and adults can be on trees and plants and are also found on bricks, stone, metal, and other smooth surfaces. SLF can also hitch a ride via vehicles, trailers, and even one's clothes.
What is currently being done
The CDFA recently granted Mark Hoddle from University of California, Riverside funds to test whether a tiny parasitic wasp, also originally from China, could be the solution to the forthcoming problem. The wasp has a needle-like appendage it uses to lay its own eggs inside the lantern fly's eggs. While developing, the wasp larvae eat and kill their hosts, and then emerge after chewing escape holes through the lantern fly eggs.
What you can do
Growers, you can inspect your trees and plants for signs of this pest, particularly at dusk and at night when the insects tend to gather in large groups on the trunks or stems of plants. Inspect trees (in particular, tree of heaven, an invasive tree itself) bricks, stone, and other smooth surfaces for egg masses which are usually very camouflaged. The female SLF covers her eggs with a creamy-white, putty-like substance that becomes pinkish-gray as it dries. After a few weeks the covering turns a darker tan and starts to crack, resembling a splotch of mud.Many photos of adult SLF show wings open, including the red underwings, but in nature this only occurs when the SLF is startled or is ready to take flight. It is much more common to see adults at rest with black-spotted, pinkish-tan wings folded over its back. Both male and female SLF have yellow abdomens with black stripes. Female SLF have a set of red valvifers at the distal end of the abdomen. When gravid (mated), the female abdomen swells to the point where they find it difficult to fly.
Barringer, L. E., Donovall, L. R., Spichiger, S. E., Lynch, D., & Henry, D. (2015). The first new world record of Lycorma delicatula (Insecta: Hemiptera: Fulgoridae). Entomological news, 125(1), 20-24.
Dara, S. K., Barringer, L., & Arthurs, S. P. (2015). Lycorma delicatula (Hemiptera: Fulgoridae): a new invasive pest in the United States. Journal of Integrated Pest Management, 6(1), 20.
Hoddle, M. (2019). Spotted Lanternfly is coming - California is getting ready, now!. California Pest Control Advisor Magazine, Aug. 2019. Vol. XXII (4),38-41.
Urban, J. M. (2019). Perspective: shedding light on spotted lanternfly impacts in the USA. Pest management science.
First, remember that the desire to avoid any kind of an interaction is mutual. Rattlesnakes are an important part of the ecosystem, feeding on rodents, birds, and other small animals.Snake season in Southern California runs from April through October, but the warmer the weather, the more the reptiles are likely to be out and about. Rattlesnakes are California's only native venomous snake, with some adults reaching up to 6 feet long. According to the California Poison Control Center notes, rattlesnakes account for more than 800 bites each year, with one to two deaths. About 25 percent of the bites are "dry," meaning no venom was injected, but the bites still require medical treatment.There are nine species live in various areas of the state and their size can vary.
According to the University of California Integrated Pest Management Guidelines(2014),the most widespread rattlesnake in California is the western rattlesnake (Crotalus oreganus), found from the northern part of the state as far south as Santa Barbara County and from sea level to 7,000 feet. Two closely related species (C. helleri and C. lutosus) are found in coastal Southern California and in the northern Sierra Nevada, respectively. The sidewinder (C. cerastes) is the smallest rattlesnake and is so named because of its peculiar method of sideways locomotion. The sidewinder is sometimes called the horned rattler because of the hornlike scales above its eyes. It is most commonly found in sandy desert areas from below sea level to 6,000 feet. The Mohave rattlesnake (C. scutulatus) ranges across the desert and foothills of southeastern California from sea level to higher elevations. The southwestern speckled rattlesnake (C. mitchellii) ranges from Baja California northward across much of the Colorado, Mojave, and Sonoran Deserts, overlapping with the red diamond rattlesnake (C. ruber) in western parts of its range and the sidewinder farther east. The Panamint rattlesnake (C. stephensi) is closely related but has a more northerly distribution in the inland desert regions of Southern California. The red diamond rattlesnake is found in Baja California and in southwestern California south of Los Angeles. The western diamond-backed rattlesnake (C. atrox) is seldom seen in California but occurs in the extreme southeastern part of the state in desert regions.
Of the nine species of rattlesnakes in this region, the Western Diamondback rattlesnake is probably the most dangerous because of its size and aggressive nature. State experts say the Diamondback can be found primarily in Imperial, Riverside and San Bernardino counties. Most trees crops that are found in this county that are at risk for hosting these snakes are avocados, citrus and dates.
This vertebrate pest can cause a threat to workers conducting routine agriculture cultural practices such as irrigating, fertilizing, and harvesting. In the deserts of Riverside and Imperial county where the laborious date palms are grown, rattle snakes can cause a threat to harvesters if orchard vegetation is left uncontrolled. The snakes are also attracted to water, so irrigators can run the risk of coming into contact with the snakes.
Biology and Behavior
Rattlesnakes are thick-bodied snakes with keeled (ridged) scales in a variety of colors and patterns. The National Wildlife Federation reported that rattlesnakes typically live for 10 to 25 years.
Most species are patterned with dark diamonds, rhombuses or hexagons on a lighter background. Rattlesnakes are ovoviviparous, which means that eggs incubate inside the mother's body. Babies are born live, encased in a thin membrane that they puncture after being born.
They are among the group of snakes called pit vipers because of the small pits on each side of the head between the eye and nostril. These pits are temperature-sensitive structures that assist the snake in finding prey, even in complete darkness. The tongue is also used to detect the scent of prey. Rattlesnakes have a specialized venom delivery system. Venom is produced in glands behind the eyes and then flows through ducts to the hollow fangs. Normally the fangs fold back against the roof of the mouth and when a snake strikes, the fangs pivot forward to inject venom.(Kardong and Bels, 1998).
The California Department of Fish and Wildlife recommends being alert and also having a sense of where a rattlesnake could be at a particular time of day. After a cold night, the snakes will try to raise their body temperatures by laying out in the sun around mid-morning. To prevent overheating during the day, they may be more active at dusk, dawn and nighttime hours.Though they are not nocturnal, in the hot summer months they may be more active at night.
The nine species of rattlesnakes found in California are not considered endangered or threatened. California Department of Fish and Wildlife Code classifies rattlesnakes as native reptiles. California residents can take most rattlesnake species on private lands in any legal manner without a license or permit, although a bag limit of two still applies. Additionally, the red diamond rattlesnake (C. ruber) is prohibited from being taken or killed by state wildlife regulation.
Most rattlesnakes seek cover in crevices of rocks, under surface objects, beneath dense vegetation and in rodent burrows, so eliminating potential shelter is critical. Adults eat live prey, primarily rodents; the young consume mostly lizards and young rodent.Controlling the vermin population in your orchard ia an important factor as the rodent borrows can become a snake's new homes. Weed management in orchards are critical during the warmer months. The vegetation can be a habitat for snakes.In addition,pruning or removing old trees from the orchard, proper disposal of the wood is important. Stacking or saving the wood in piles create a habitat for the rattlesnakes.
Structures for farming operations can vary in size and age. Chemical sheds, equipment garages, machinery shops are infamous to hosting snakes. In summer, rattlesnakes may be attracted to cool and/or damp places, such as beneath buildings. Sealing all cracks and other openings greater than 1/4inch can prevent them from entering. Gaps beneath doors are often large enough to permit snakes to enter, especially young ones.
According to the University of California Integrated Pest Management Guidelines(2014),rattlesnakes add to the diversity of our wildlife and are important members of our ecosystem. They can reduce the number of disease carrying rodents and other pest species. In general, they should be left alone, whenever possible, especially in wildland areas. Nonvenomous snakes, such as gardener snakes should also be left alone wherever found.
California Department of fish and Wildlife. https://www.wildlife.ca.gov/Keep-Me-Wild/Rattlesnakes. Accessed 20 June 2019.
California Poison Control. https://calpoison.org/topics/rattlesnakes. Accessed 20 June 2019.
Kardong, K. V. and Bels, V. L. 1998. Rattlesnake strike behavior: kinematics. Journal of Experimental Biology, 201(6), 837-850.
National Wildlife Federation. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Reptiles/Rattlesnakes. Accessed 20 June 2019.
Salmon, T. P., D. A. Whisson, and R. E. Marsh. 2006. Wildlife Pest Control Around Gardens and Homes. 2nd ed. Oakland: Univ. Calif. Agric. Nat. Res. Publ. 21385.
Todd, B., T.P. Salmon, D.A. Whisson and R.E. Marsh.University of California Integrated Pest Management Guidelines http://ipm.ucanr.edu/PMG/PESTNOTES/pn74119.html. Accessed 20 June 2019.
Walter, F. G., U. Stolz, F. Shirazi, J. McNally. 2009. Epidemiology of severe and fatal rattlesnake bites. Philadelphia: American Association of Poison Control Centers' Annual Reports. Clin. Toxicol. 47:663-669.
- Author: Ben Faber
Boom, just when you think everything is going fine, you run across a reminder that there are little things going on in the orchard that are out of our control. In Goleta, I just ran across these crick-side, crook neck fruit that are a reminder that we just had about 3 weeks of foggy weather (in the fall, when it's supposed to be in the spring) and then a week of hot weather which is just the condition to create this calcium imbalance and distorted fruit. It's no big big deal, unless it was all over tree. Just more of an oddity. Harvest time is past this year so didnt expect to see it on this new fruit.
At avocado harvest time, growers are in the orchard checking things out a little more closely and to see what is going into the bins…..and they see some unusual shaped fruit. Here's what's been popping up and some possible explanations.
Crick-side - First described by Dr. J. Eliot Coit as kink-neck and later by Horne (1931) as kink-side. Finally, the name crick-side (Horne, 1934) was adopted. It is characterized by a definite depression on one side between the stem end and the larger portion of the fruit causing a distortion. In some cases, the area of depression turns black and the fruit drops. In other cases, the fruit grows and matures but the distortion remains. Crick-side is usually found on trees carrying a heavy load of fruit. It has been suggested that high temperatures or temporary water-stress may relate to the occurrence of crick-side, but no definite determination as to its cause has been made.
Carapace Spot - First described by Horne (1929), the name carapace-spot was chosen because of the resemblance to a turtles' back. This external blemish is corky and usually cracked into somewhat regular, angular divisions. The flesh under the carapace spot is undamaged, but exterior appearance is such that the fruit is reduced in grade. Slight rubbing or brushing of tender young fruit on leaves or stems appears to cause this corky growth to start. Fruit on trees exposed to strong winds are more apt to develop the trouble. Windbreaks should reduce injury in windy areas.
Photo: Avocado thrips damage, carapace damage and greenhouse thrips damage.
Sunblotch - This is a viroid that can affect fruit, leaves, and stems with a yellow or reddish streaking, cause a compacted growth and willowy growth habit. The streaking in the fruit is usually depressed and doesn't extend the length of the body.
Sunburn - Fruit exposed to full sun may be injured by sunburn. This occurs when trees defoliate, or partially defoliate, from any of several causes, leaving the fruit exposed. It is normally most severe on fruit on the south and southwest portion of the tree. Sunburn shows as a pale yellowish area on the exposed side of the fruit. Often the center of this area turns brown to black and may wither.
Ring Neck - This trouble has been observed occasionally, particularly with Hass. The cause is unknown but is believed to be related to soil-plant water deficiency at a critical time. A ring of tissue on the pedicel just above the attachment to the fruit dies, turns black and peels off. If only superficial, the fruit remains on the tree. Growth may be retarded because the restriction impedes movement of nutrients and water outward to the fruit. Most severe in humid coastal areas.
Embossment - Occasionally, and particularly on Fuertes, a section of the surface will be raised slightly or be a darker or lighter color. This is referred to as a sectional chimera or genetic mutation.
Healed over damage - if fruit has mild damage that allows it to heal over (remember avocado fruit expand by cell multiplication not enlargement), then a scar is left, such as this likely amorbia feeding
Cuke - As in cucumber but not a squash. These are seedless fruit that can most often be seen from a fruit set in cooler weather or due to some hormonal stimulus. We don't know the reason, but seems to occur more commonly along the coast.
Double Fruit - In some instances there may be a normal shaped fruit with a single cuke attached ot in some cases there is a double ovary and two fruit are attached.
Woody Avocados - For some unknown reason, avocado fruit will form into a grotesque woody structure hardly resembling an avocado. The cause is genetic and non-transmissible.
Sources: R.G. Platt - California Avocado Society Yearbook 1972-73 and Reuben Hofshi and M.L. Arpaia Yearbook 2002.