Codling Moth Arrival and Biofx Setting

Pheromone lure with trapped moths.

To determine when flight begins for codling moth, commercial growers make use of pheromone traps.  Once moths have been trapped for  two consecutive days in a row, a biofix is set  that initiates the beginning of growing-degree-day calculations.  We know that at approximately 100 degree days after the biofix date codling moths begin to lay eggs and those eggs begin to hatch at approximately 250 degree days after biofix.  It is this information that aids in the timing of necessary sprays for codling moth so they do not damage fruit.  Growers wishing to time sprays based on egg development and hatch (larval stage) should make an application of an insecticide at 250 DD (base 50 degrees F) after the first sustained capture of males in the sex pheromone traps.  Here is a Detailed Growing Degree Day Model for Codling Moth.   

 

We have now established a biofix for CM for this spring and it was May 26.  You may apply insecticides that need to be present before egg laying at about 50-75 DD or you may apply insecticides that target early egg laying period at 100-200 DD.  Since the biofix date, we have accumulated approximately 9 DD, but with the projected hot temperatures for the comming week, we will have to keep a close eye on the degree days for the first application of an ovicide.  It will soon be time time for the home grower to apply a spray to target early egg laying. 

For the home orchardist who does not have the benefit of a weather station or other means to calculate degree days, a simple tree growth stage time table can be followed.  Codling moths usually start flying at bloom time or just after bloom time at petal fall and approximately at the same time as plum curculio.  Eggs laid by these moths begin to hatch about two weeks after petal fall, depending on the weather. You can apply the first codling moth spray at this time, about two weeks after petal fall, to prevent larvae from entering the fruit. Because most insecticide residues last 7 to 10 days and moths are continuously present throughout the summer, apply a spray every 7 to 10 days to prevent later broods of codling moth larvae from entering apple and pear fruits. If using a natural product like Spinosad, then spray after every rain due to washoff.  Always follow the label directions of any spray you may use.

Several insecticides can be used for codling moth control including acetmaprid and/or spinosad.  Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit and Vegetable Insect Killer.  This is a ready to use product that contains .006% acetamiprid, and is also available in a concentrate containing .5% acetamiprid.  Acetamiprid is a synthetic organic compound of the family of chemicals that acts as neonicotinoid insecticides. Acetamiprid is a contact, translaminar insecticide for sucking-type insects and can be applied as a foliar spray.  Translaminar insecticides are absorbed by leaves and can move through the leaf to the opposite surface they contact. They are not truly systemic and do not move throughout the entire plant. Acetamiprid acts on a broad spectrum of insects, including aphids, thrips, plum curculio, apple maggot and Lepidoptera, especially codling moth.  When sprayed in the evening at sunset, it will not harm bees or other beneficial insects once it is dry. Be sure to follow all label directions on the bottle for proper application.

An all natural approach is also available in the form of Bonide’s Captain Jack’s Dead Bug Brew.  Captain Jack's Deadbug Brew® contains Spinosad (spin-OH-sid), a product first isolated from a naturally occurring soil dwelling bacterium that was collected on a Caribbean island from an abandoned rum distillery. Deadbug Brew® kills bagworms, borers, beetles, caterpillars, codling moth, gypsy moth, loopers, leaf miners, spider mites, tent caterpillars, thrips and more! Use on fruits, vegetables, berries, citrus, grapes, nuts and ornamentals and approved for organic gardening.  

Both of the above products will kill Codling Moth larvae and need to be sprayed just prior to the emergence of the larvae,  which is between 100 to 250 DD after biofix.  Since we are not yet at or near 100 DD after biofix, your trees can be sprayed in about 7 to 10 days, depending on the amount of rain that may fall at night between now and then.  Typically after 1" of rain, these sprays will have been washed off and will need to be sprayed again to be effective.

For additional information, see the following fact sheets which are available from local university extension services:

https://ecommons.cornell.edu/bitstream/handle/1813/43086/codling-moth-FS-NYSIPM.pdf

http://extension.psu.edu/plants/tree-fruit/insects-mites/factsheets/codling-moth

 Reference in this publication to any specific commercial product, process, or service, or the use

of any trade, firm, or corporation name is for general informational purposes only and does not

constitute an endorsement or certification of any kind by Royal Oak Farm.

People using spray products assume responsibility for their use

in accordance with current label directions of the manufacturer.

Plum Curculio Season is On the Horizon

Plum Curculio Ovipositing Egg

With apple scab season in our midst, and petal fall coming to an end, it is time to turn our attention to several insect pests. Plum curculio (PC) is one of the most difficult insect pests to contain.  They enter the orchard from the perimeter after the adults pass the winter hidden under leaves, along fence rows, in brush piles, rock walls and in other protected places. In spring when the weather warms up (mean temperature 60°F. or maximum temperature above 75°F.), about the same time apples are blooming, the adults become active. The adult plum curculio beetles, pictured to the left, emerge right around or just after petal fall, to feed on apple buds, flowers, leaves and young fruit.  The duration of full bloom to petal fall is usually about 5 to 10 days.  From petal fall to fruit set is generally another 5 to 10 days, depending on temperatures.  Once the fruit sets, female beetles cut holes in the young fruit and deposit one egg in each cavity. 

 

 

These sites, called oviposition stings, are easily identified by their crescent shaped cuts. Unlike codling moth, the larvae of plum curculio rarely cause damage to the fruit. The fruit is primarily damaged superficially by the egg-laying and feeding by the adults. These "stings" will cork over and cause an indentation in the fruit as it matures making it look deformed and unsightly.

The question then becomes, how do we control them??  Pesticide application at this time is very important for plum curculio control. To prevent fruit drop, and due to toxicity to bees if there are still blooms on the trees, do not use carbaryl (Sevin®) or any pyrethrin based spray as these are highly toxic to honey bees and other pollinators as well as any beneficial insects. Any other pesticides should be applied int he evening when the honey bees have returned tot heor hives.  For home growers, an acetamiprid spray such as Ortho® Flower, Fruit & Vegetable Insect Killer Ready-Spray is a deterrent.  If no blooms are present  on any trees, a pyrethrin based spray can be used as a deterrent, even though there may be no fruit.  Picking up and disposing of any fallen fruit will reduce problems with plum curculio, other insects, and many plant diseases. For conventional growers, Avaunt or Assail are two choices you might use, based on your codling moth protocol and your apple maggot protocol.

For a pure organic spray, the two most frequently used insecticides are Surround® and Pyganic®, both certified organic. The organic products may need to be sprayed multiple times for complete control at 7 to 10 day intervals or after any rain. And, as always, follow all label directions on any spray product. 

For a complete Fact Sheet on Plum Curculio, consult the Cornell University Plum Curculio Fact Sheet and for an in depth look at this pest.
__________________________________________

This publication contains pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registration, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these  recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned.  The author assumes no liability resulting from the use of these recommendations.

Tree Growth Stages, Main Pests, and Spray Guide

If you have a Home Orchard or just a few apple trees in your back yard, and if you have not thought about how to handle those pest problems you had last season yet, now is the time to actively examine a spray protocol  for your fruit trees!  And start right away, before it is too late and the pests have a chance to establish themselves in your trees!  The question everyone needs to ask before spraying is “Do I want to spray or not?”   Well, unfortunately, in northern Illinois we have four main pests that we will almost always have to spray for.  This is pretty much true for any area east of the Rocky Mountains.

The decision to spray or not depends on how much fruit loss you are willing to take. That is your threshold.  If you can accept some fruit loss, then the need to spray diminishes greatly.  But if you only have a few trees and some fruit damage may mean losing half your fruit, then spraying becomes more important.  Let’s meet our top four pests in northern Illinois,  southern Wisconsin, and in most of the states east of the Rocky Mountains. 

 The Four Main Pests

 

The four main pests that we face in apple orchards here in our climate zone of 5/5A are apple scab, plum curculio, codling moth and apple maggot, in that order. For more information on these and other potential apple tree pests, visit our web site Growing Guide page.  But how do we know when to spray for them if it is a last resort to protecting our fruit? 
 

All tree fruit have several distinct growth stages as the fruit matures.  Knowing and identifying those growth stages is  very important for the home grower because recommendations and spray timing for spray applications are linked to these specific growth stages.  The chart below shows the common growth stages for apple trees.  

Tree Growth Stages (Phenology)

 

Since the average home grower does not have access to their own weather stations or degree day calculators, the fruit tree development stages play an ever greater  role in pest management for the average grower.  Most spray schedules (protocol) follow the tree development stages to aid in the timing of sprays so they are most effective.  It is important to note that many diseases and some insects can only be controlled by spraying before they can be seen like apple scab.  Spraying less frequently or at the wrong time will typically result in poor results.  And, spraying more frequently will not necessarily give greater control.

The tree developmental stages or tree phenology gives us a guide as to when to spray, but what do we spray if we have to spray?  If we consult some of the various spray guides available to the home grower, we will find that most of the spray guides provide us with the tree’s development stages (phenology) and the insects or diseases that frequently  occur during each of theses stages.  So the tree phenology serves as timing guide when the application of a particular spray is recommended in order to control specific insects or diseases at the right time.   The following spray guide for apple trees will give us the time to spray based on tree phenology, the pest to spray for and the product recommendation for that pest(s).

Apple Spray Guide

This particular spray guide is included in “Managing Pests in Home Fruit Plantings” from the Purdue University Extensions Publication web site or our web site as a free download.  It goes into detail as to the various products available for spraying that include both conventional and organic alternatives.  The publication includes apples,  pears, peach, cherry, grape, strawberry and raspberry guides as well as the phenology charts for each fruit type.  For recommendations on spray products for the Home Orchard visit our spray product recommendations.

Reference in this publication to any specific commercial product, process, or service, or the use

of any trade, firm, or corporation name is for general informational purposes only and does not

constitute an endorsement or certification of any kind by Royal Oak Farm.

People using spray products assume responsibility for their use

in accordance with current label directions of the manufacturer.

Revisiting Critical Temperatures for Fruit Trees

With the predicted colder night temperatures we are about to see, it's always a good idea to revisit the critical temperatures that can cause frost or freeze damage to fruit trees, specifically apple trees.  We are currently at tight cluster to pink to bloom here in northern Illinois with a forecast of night temperatures in the high 20's this weekend. Fortunately, our trees haven't progressed to far this spring, but we could see some bloom this weekend.   This spring has marked another unprecedented weather pattern that raised our temperatures in late March and early April and is dropping our temperatures going into mid-May to way below normal.  The early warm temperatures accelerated bud swell, and the lower temperatures that are anticipated present the threat of frost or freeze damage to new leaf and bloom tissue.  It seems that each spring since about 2012, we have been on the verge of critical temperatures for frost or freeze damage with our fruit trees. 

Dark brown centers and signed appearance of the petals
indicate that both king and side blooms were killed in a
freeze the morning this picture was taken.  (Photo credit:
Mark Longstroth, MSU Extension)

As the trees develop in the spring and buds start to swell, they lose the ability to withstand the cold winter temperatures that they could withstand in dormancy during the cold winter months. The young, actively growing tissue can then be damaged or even killed. Swollen fruit buds can better withstand temperatures in the teens without any damage. As the buds open, temperatures in the low 20s can cause harm, but sometimes leave other buds undamaged.  As growth moves from green tip to 1/4” green to 1/2” green to tight cluster to pink in apple trees, temperatures in the upper 20s can cause considerable harm to an early blooming tree. Near bloom, the range between slight and severe damage can be very small. Freezing temperatures of 28 degrees F. will result in about a 10 percent loss and 24 F will result in a 90 percent loss, as indicated by the charts down below.

The dark brown center of this apple flower  indicates it was
killed by a freeze. (Photo credit: Mark Longstroth, MSU Extension)

In a radiation freeze with clear, calm conditions, fruit at higher elevations or in the tops of trees will be less damaged than those at lower elevations, since colder air is more dense than warmer air and sinks to ground level, pushing the warmer air up. The percent of flowers killed in a frost may or may not relate directly to lost yield later in the season. With large-fruited fruits such as apples, peaches, plums and pears, the loss of 50 percent of the flower may not be devastating since we may only want a small percentage of the flowers to become fruit, meaning that fruit thinning may be totally unnecessary.  So the stage of bud and bloom development determines how susceptible any given fruit crop is when freezes occur.  For more information on what those critical temperatures are that can cause freeze damage to trees during development, I have added two charts on the Critical Temperatures For Frost Damage on Fruit Trees from Utah State University below that you can download by clicking on either chart below.

(Click on the photos to download the chart in PDF format.)

 

Given the weather patterns we have experienced so far this spring a spring frost could still be possible.  Once the fruit has set, then the critical temperatures that can damage the fruit become lower.   We will need to constantly assess the stage of development our trees are at over the next weeks and their susceptibility to possible freeze injury.

If we continue in this spell of colder weather, apple trees will continue to develop more slowly, but once they begin showing tight cluster, pink and bloom, the critical temperature rises from the low 20’s to the high 20s, to levels just below freezing at bloom time, which is the most critical time to get frost damage.