Cydia pomonella

Written by: Elizabeth Garofalo, UMass Amherst

Content adapted from MyIPM/Bugwood Apps

Overview

Codling Moth was introduced to North America by European settlers and has since become an established pest in all pear producing regions of the United States and Canada. Larvae cause two types of fruit damage; deep entry, where larvae burrow down into the core of the fruit, pushing frass out as they go and shallow entry where feeding may also occur but no tunneling is present. Both forms of damage render fruit unmarketable. Second generation larvae cause the most damage.   

Biology

The adult codling moth is gray-brown with alternating lighter gray and white bands across the wings. The wings are marked at the back end by a coppery area that helps distinguish codling moth from other similar moths. Newly hatched larvae are small, the black head is twice the width of its pale yellow body at this stage. Mature larvae are pinkish-white with a brown head. Codling moth overwinters as a later stage larva. Pupation occurs during bloom. First adults emerge at 150DD, base 50 ℉. when counting from January 1. Warmer spring temperatures can accelerate the growth of codling moth, leading to earlier developmental milestones (like egg laying and hatching). Females can lay up to 100 eggs. Early season eggs are generally laid on leaves whereas later generations are usually laid on fruit.  There can be anywhere from one to four generations.      

Monitoring

Pheromone traps should be hung at bloom, on the north side of the tree at eye level. Hang traps in the orchard where moths are most likely to enter from alternate host sites. Check traps at least once weekly. First insecticide applications should be made ~ 250DD (base 50) after sustained catches in pheromone traps. First insecticide applications for second-generation should be made at about 1,400 DD to 1,600 DD, using the same biofix as previous spray timing.

Management

Non-Chemical Control: Remove abandoned orchards and other alternate hosts, where practicable. Trunk banding can be a useful method of reducing codling moth pressure. Cardboard wrapped around trunks before larvae move to cocooning sites will cause them to pupate on the cardboard, which is subsequently removed and destroyed prior to adult emergence. Hot water treatment of storage bins can destroy a number of the overwintering larvae. Mating disruption and Surround are also effective non-chemical control methods.

Chemical control: Many insecticides are effective against codling moth when applied at the right timing and insect development stage. Resistance to organophosphates, however, has been documented in some regions of Washington and Oregon and is likely in other regions/orchards where codling moth is a problem.

Written by:  Elizabeth Garofalo

Overview

Pear pyslla Cacopsylla pyricola is one of the more problematic insect pests of pear. It is widely distributed, has several generations and life stages, has an unusual ability to develop chemical control resistance, and where left unchecked, secretes copious amounts of honeydew that grows a black fungus making fruit unmarketable. Heavy infestation can also result in tree stunting (psylla shock), reduced fruit set and size, and even death with prolonged infestation.

Biology

Adults are dark red-brown in color, with four wings folded like a pup tent over the back. Nymphs have five stages, beginning as yellow wingless 3 mm. long when newly hatched, turning darker, and then finally with fifth-instar have wing pads. Adults hatch from overwintering in bark crevices and under bark in the early spring on sunny days when temperature rises above 50 degrees F. Most eggs are laid by bud break. Eggs hatch by petal fall and nymphs move to axils of leaf petioles and stems. They suck on sap which is changed to honeydew and given off as droplets which surround the nymph. Nymphs go through five immature stages and there are three generations per season!

Monitoring

Look for pear psylla adults on the first nice sunny day of spring before bud break. They can also be monitored using yellow sticky traps. The summer treatment threshold for pear psylla is one psylla nymph/three leaves.

Management 

Start with oil sprays in early spring, which deter egg laying. Then beginning at bud break use insecticides with good-excellent efficacy against pear psylla. Focus on early season management to keep psylla from becoming a season-long problem. Pyrethroids (Asana, Brigade, Danitol, Warrior) are good choices early unless resistance is suspected. Esteem, an IGR, has to be applied at the white bud stage then again at petal fall. 14-days after petal fall, Agri-Mek plus oil should give season-long control. Neonics (Admire, Actara, Clutch, Assail), Proclaim, and Portal require two or more applications for adequate control. Centaur and Movento, when applied at the correct timing (nymph hatch), give good control of psylla. Neem compounds ( Aza-Direct and Ecozin 3% EC) require multiple applications to suppress pear psylla. And Surround is effective to deter egg laying by adults and nymph feeding, but multiple applications and complete coverage are necessary.

Pear psylla has become quite resistant to conventional insecticides (pyrethroids). Difficulty controlling psylla with these indicates you have a resistance issue, and you need to try some of the newer chemistries/registrations. Be sure to rotate active ingredients to prevent/delay resistance development. Oil and Surround are good applications too because resistance won’t develop.

Avoid excessive, succulent shoot growth by cutting back on pruning and nitrogen fertilization. Prune after bloom if possible. Summer prune to remove water sprouts.

For an excellent discussion on pear psylla management, see The Jentsch Lab: https://blogs.cornell.edu/jentsch/?s=psylla

Adapted from ‘Common Tree Fruit Pests,’ Angus Howitt, Michigan State University, 1993 and 

Extension Bulletin E154 “2015 Michigan Fruit Management Guide for Commercial Fruit Growers” https://shop.msu.edu/product_p/bulletin-e0154.htm

Insecticides

Oil | Lime sulfur | Surround | Abba | Actara | Admire Pro | Agri-Flex | Agri-Mek SC | Agri-Mek EC | Assail |Belay | Centaur | Delegate | Endigo | Esteem | Exirel | Gladiator| Leverage | Movento | Nexter | Portal | Proclaim | Rimon | Voliam Flexi | Voliam Xpress

Conotrachelus nenuphar

Written by:  Elizabeth Garofalo, UMass Amherst

Content adapted from MyIPM/Bugwood Apps

Overview

Plum curculio (PC) has time and again been identified by pome fruit growers as one of the single most destructive insect pests in the orchard. There are four types of wounds caused by PC, however, oviposition is the most recognizable of these. When the female lays her eggs, she sweeps her ovipositor in an arc along the surface of the fruit. This motion causes the distinctive “half moon” scar. When an egg hatches, the larvae tunnel into fruitlets, begin to feed, and the fruitlet will generally drop to the ground prematurely. When the egg is not viable, or the female decides that she does not want to lay an egg on a particular fruit, the scar remains and can be seen at harvest, often making the fruit unmarketable.

Biology

Plum curculio is a snout-nosed beetle, aka a weevil. The adult is small, about 6 mm, mottled black, grey and brown. When handled it will often “play dead” in an attempt to fool animals that might prey on it. The larvae is a whitish, legless grub, it's feeding on the inside of fruitlets is what will cause premature drop. Larvae then crawl out of the fallen fruitlets into the soil where they pupate. Adults emerge from the soil after ~16 days. They then move around, feeding here and there,  until cold weather drives them into hibernating spots. Commercial orchards, generally, do not have overwintering populations within their borders. Wild hosts (abandoned orchards, crab apples, etc.) on the other hand, are a prominent source of adult curculio. These outsiders will migrate into your orchards right at petal fall, when temperature and moisture are optimal.

Monitoring

Fruitlets should be monitored beginning at about 5 mm diameter along orchard borders to determine if new injury is occuring. If fresh oviposition scars are observed, a first cover border spray should be made. Cool wet weather will prolong PC activity. Continue to monitor for fresh scars. If more are found, a second cover spray may be needed.  

Management

While there is promising work with beneficial nematodes underway, management of plum curculio relies heavily on petal fall, first and second cover insecticidal applications. The first insecticide application should be made to the whole orchard in order to clean up any PCs that have migrated into the inner part of the orchard. Surround is an organically approved material that can also be complementary to conventional management strategies. Surround applications at the onset of petal fall and continue to reapply weekly to maintain coverage and deter egg laying.  Do not apply insecticides until bloom is completely finished to reduce unwanted pollinator exposure.  When using pre-mixes, ensure the modes of action in the material are effective against more than one of the pests you are managing.  For example, a petal fall spray of Voliam Flexi will be effective against both plum curculio and european apple sawfly. This material has moderate toxicity for honeybees and low toxicity to some predatory insects (not too shabby). For information on rainfast characteristics of some insecticides, see the following article in Fruit Gower’s News:

http://fruitgrowersnews.com/news/rainfast-characteristics-insecticides-fruit-reviewed/

 

Orthosia hibisci

Overview

Speckled green fruitworm is one of several members of the Noctuidae fruitworms family which cause damage to fruit and foliage of pome and stone fruit. It was introduced from Europe, the adult being a nocturnal moth, however, it is the larval stage, particularly the large ones that cause unacceptable damage to fruit.

Biology

Green fruitworm overwinters as an adult moth which starts flying (at night) and lays eggs in the spring. Larvae hatch and go through six instars, the later instars being a quite large (one inch) green caterpillar with yellow/white longitudinal stripes. Larvae feed on flowers, fruit and foliage where they can roll leaves similar to true leafrollers. Individual fruitworm larvae can feed on many fruitlets during the post-bloom period, however, many of these damaged fruits will fall off. Fruit that persists to harvest will have deep corky scars and indentations, which is also similar to leafroller feeding from the overwintering generation.

Monitoring

Examine 20 flower/fruit clusters on 5 trees throughout the canopy from pink to first cover. If two or more larvae per tree are found, or there is evidence of feeding damage, treatment is recommended. Pheromone traps can also be deployed to monitor the presence and relative abundance of green fruitworms.

Management

Pre-bloom insecticides are advised, and pyrethroids are the best choice, however, they can be hard on beneficial insects when applied at this time. Post-bloom insecticide applications targeting other insects are generally effective too. B.t. (Dipel) is effective if applied early before the larvae get too big.

Tetranychus urticae

Content adapted from MyIPM/Bugwood Apps

Overview

Two-spotted spider mite is a secondary (non-fruit damage) pest of apple and pear. It is widespread in range, has multiple generations per season, easily develops resistance to miticides, and is particularly problematic when it is dry and moves from the ground cover into fruit trees.

Biology

Adults are pale yellow to dark green, brownish, or faintly orange. Males are smaller than females, have a distinctly pointed abdomen, and darkish areas on each side of the body. Females are more oval, and when newly hatched have namesake distinct dark areas on each side of the body, which becomes more blotchy and irregular when feeding commences. Nymphs also have distinct two spots. TSSM overwinters under bark or in the ground cover. In spring they typically move to weeds and grass where they feed. In summer they crawl into the canopy especially when it gets dry or the orchard floor is mowed. Once in the tree a serious infestation can develop and cause damage which is grayish bronzing of foliage in apple and solid dark-brown spotting of pear leaves.

Monitoring

Check foliage for mite presence beginning in early summer. 10 leaves from 10 trees should be averaged for a count, Chemical treatment is advised if there are six or more mites per leaf. Also, check foliage touching ground cover on lower limbs. Summer oil sprays are advised, but a spring oil spray is not effective on TSSM because – unlike European red mite -- they are in the groundcover. If miticides are necessary, only use if over threshold and rotate chemistries for resistance management. If you can identify mite predators, then one predator per leaf on average may justify holding off on applying a miticide. (See http://www.ipm.msu.edu/insects/twospotted_spider_mite for help.)

Adapted from ‘Common Tree Fruit Pests,’ Angus Howitt, Michigan State University, 1993

Management

Chemical Control

Summer applications of miticides are indicated. Early season oil applications are not effective.

Specific Resistance Issues

Resistance is likely when miticides are not rotated. Be sure to rotate miticide classes when choosing chemical control.

Non-Chemical Control

Minimize weed growth, particularly broadleaf weeds, in the orchard. Mow frequently to keep groundcover short, but avoid mowing during hot/dry spells.

Adapted from Extension Bulletin E154 “2015 Michigan Fruit Management Guide for Commercial Fruit Growers” https://shop.msu.edu/product_p/bulletin-e0154.htm

 

EXTRAS

From UC Statwide IPM Project: Webspinning mites produce a characteristic blackening of pear leaves when they feed. Pear trees can tolerate fewer webspinning mites than European red mites. Usually two to three mites feeding near the midrib of a leaf produce black areas from the midrib to the margin. This blackening may appear even after mites have been controlled, especially if a period of hot weather follows the spray application. High mite populations may cause defoliation. Severe defoliation can stunt fruit and may cause the trees to bloom in fall, thus reducing next year's crop. However, if defoliation is limited to water sprouts in the top or interior of the tree, it will not adversely affect the crop or tree.