July 3, 2018

Japanese Beetle Emergence

Figure 1.
Japanese Beetle emergence has begun here in Northern Illinois.  I noticed the first beetles on Monday and today they were in full view on our Honeycrisp trees (Figure 1).  Due to the large amount of carbohydrates produced by the Honeycrisp trees, which is what makes the variety so sweet, the Japanese Beetle is seemingly attracted to it just like we are!  Honeycrisp seem to be the first leaves that attract them and then they move on to raspberries and several other berry varieties.  

 Monitoring for Japanese Beetle

Adult Japanese beetles emerge from the soil and live from 30 to 45 days feeding on plants over a four-to-six-week period.  The adults produce aggregation pheromones that attract individuals (both males and females) to the same feeding location. Adults can fly up to five miles to locate a feeding site; however, they tend to fly only short distances to feed and lay eggs.   The adult beetles normally emerge during the last week of June through July. The first beetles out of the ground seek out that suitable food , like Honeycrisp, and begin to feed. These early arrivals then begin to release that aggregation pheromone (odor) that attracts additional adults. Newly emerged females also release a sex pheromone that attracts males. After feeding and mating for a day or two, the females burrow into the soil to lay eggs at a depth of 2 to 4 inches. Females lay 1 to 5 eggs before returning to plants to feed and mate. This cycle of feeding, mating and egg laying continues until the female has laid 40 to 60 eggs. Most of the eggs are laid by mid-August though adults may be found until the first frost. The eggs hatch in 8 to 14 days and the first instar larvae dig to the soil surface to feed on roots and organic material. The first instars shed their skin (molt) in 17 to 25 days. The second instars take 18 to 45 days to mature and molt again. Most of the grubs are in the third instar by late September and by October they dig deeper into the soil to overwinter. The grubs return to thesurface in the spring as the soil temperature warms, usually in mid-April. The grubs continue their development and form a pupa in an earthen cell 1 to 3 inches in the soil. 

Figure 2.
When you see those first few beetles, that is the time to begin you plan of attack.  Those first few beetles are the food source scouts that will emit the aggregation pheromone letting other beetles know that a feast is on! The Japanese beetle adults feed through the upper leaf surface (epidermis) and leaf center (mesophyll), leaving the lower epidermis intact. Adults usually avoid feeding on tissue between leaf veins, resulting in leaves appearing lace-like or skeletonized (Figure 2). Controlling those first few beetles can give you a head start on stopping the feeding/mating cycle.

 Control for Japanese Beetle

There are some control options for the adult life stage One is physical removal and/or trapping of adults:  Removing beetles by hand, or trapping, may provide adequate protection  for  small plantings  when  beetle  numbers are low.  However, Japanese  beetle  adults  are capable  of  migrating  from  other  areas,  and  the presence  of  beetles  on  or  near  a  plant  will  attract more   beetles.  Consequently,   use   of   Japanese beetle traps often attracts more beetles, and results in subsequent damage to plants. 

Figure 3.
The other alternative is chemical control of adults:  Several insecticides are labeled  for  use  against  adult  Japanese  beetles.  Always  follow  label  directions.    Treat  foliage  and flowers thoroughly.  For optimal control, apply in the late afternoon when beetles are most active. Several insecticides can be used for apple maggot control including those used for codling moth and apple maggot control like acetmaprid.  There are others like Sevin, but I do not recommend the use of Sevin since it is toxic to bees and to beneficial insects.   Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit & Vegetable Insect Killer (Figure 3).  This is a ready to use product that contains .006% acetamiprid, a synthetic organic compound of the family of chemicals that acts as neonicotinoid insecticides. Acetamiprid is a contact insecticide for sucking-type insects and can be applied as a foliar spray or a soil treatment.  When sprayed in the evening at sunset, it will not harm bees or other beneficial insects. 
If you do choose to use chemical controls make sure that the plant you are applying to is listed on the label as well as Japanese Beetles. If controlling Japanese Beetles on food crops such brambles or apples – make sure to follow the harvest-restriction date on the label. Always READ and FOLLOW the label and do not apply at rates higher than listed.

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.

July 2, 2018

Time to Start Monitoring for Apple Maggot

Fig. 1
Last season we trapped the first apple maggot fly on June 30. at about 1150 Degree Days from March 1.  We are at 985 DD as of today at 6:38 PM, so it is time to get out the  apple maggot traps  and get them set.  It only takes one trapped fly to  determine that they have arrived to the orchard!  The apple maggot (AM) is native to the Midwestern US and is considered a primary pest, along with plum curculio (PC), and codling moth (CM), which have been covered in previous posts. The adult apple maggot fly resembles a small housefly in size, with a black body, eyes of dark red, with the thorax and abdomen having distinctive white or cream colored bands. The AM is distinguished from other similar, and closely related flies, like cherry fruit fly and black cherry fruit fly, by the variation in dark banding on its wings (See Fig. 1).  

Apple Maggot damageA
Fig. 2
The AM overwinters in the pupal stage in soil. As soil temperatures rise in early spring, development of pupae commences.  The adult fly first emergence begins shortly thereafter (early summer, mid to late June in upper Illinois). A feeding and mating period (pre-oviposition) of approximately 7-10 days is followed by egg laying directly under the skin of the apple. Females may deposit eggs over an approximate 30 day period laying as many as 300-500 eggs.

Fig. 3
Egg-laying punctures cause dimples and distortion in the outer flesh of fruits. These punctures appear as pinpricks on the fruit surface. Larvae tunnel throughout the fruit leaving irregular trails.(Fig. 2) As eggs hatch, larvae funnel through fruit flesh leaving a winding brown trail.(Fig. 3)  Egg laying usually ceases in early to late August; however, it may continue longer if drought conditions exist throughout August.

Monitoring For Apple Maggot

Fig. 4
When monitoring for AM, the apple maggot fly tends to show a preference for golden delicious varieties, but no variety is immune from attack.  Sticky red spheres are effective monitoring devices for adult AM flies (Fig. 4). Females are attracted to the sphere for mating and egg laying activities and are trapped by the sticky coating. Hang traps shortly before expected adult emergence (mid to late June in upper Illinois). First emergence may be detected by checking traps daily until the first fly is spotted on the trap.

Hang the sphere in the proximity to fruit at eye level on the perimeter of the south or southeast side of the tree. Attach the ball in a sturdy stem about 1 foot above a fruit cluster of approximately 6-10, cleaning out the foliage and other fruit for at least 18 inches to sides and top of the trap so it is easily visible. The spheres attract the insects that come within a few yards of them; therefore, capture of ONE AM on any one trap at a time would indicate the need for an immediate control application. Once the pesticide is applied, AM captures are disregarded for the period during which the protective spray is effective (varies according to pesticide used).

Control for Apple Maggot

Fig 5.
Several insecticides can be used for apple maggot control including those used for codling moth control like acetmaprid and/or spinosad.  Acetamiprid is a soft, conventional control and is available as  Ortho Flower, Fruit & Vegetable Insect Killer (Fig. 5).  This is a ready to use product that contains .006% acetamiprid, a synthetic organic compound of the family of chemicals that acts as neonicotinoid insecticides. Acetamiprid is a contact insecticide for sucking-type insects and can be applied as a foliar spray or a soil treatment. 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.  Be sure to follow all label directions on the bottle for proper application.

Fig. 6
An all natural approach is available in the form of Bonide’s Captain Jack’s Dead Bug Brew (Fig. 6).  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.

As always, be sure to follow all label directions on the bottle for proper application.

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


Reference in this blog 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, recommendation, or certification of any kind by Royal Oak Farm, Inc.   People using such products assume responsibility for their use in accordance with current label directions of the manufacturer.

June 19, 2018

Rainy Weather Means Apple Scab and More Apple Scab

This 2018 growing season thus far is proving to be one of the more severe apple scab seasons.  As of today, June 19, we have had eight apple scab infection periods and have had several of those infection periods last for more than 36 hours and two of them lasting more than 48 hours. That has made it nearly impossible to control primary scab outbreaks.  With that being the case, we are at a point of now having to protect fruit from secondary scab.

Fig. 1
Season-long control is difficult if primary infections develop, like those in Fig. 1, which produce secondary inoculum placing fruit at risk for secondary, conidial infections.   With primary ascospores possibly depleted, we will have to continue to monitor scab infection events and maintain spray coverage accordingly for at least two more weeks, if not longer, since we have found primary lesions, like those in Fig. 2 on McIntosh and McIntosh hybrids like Cortland and Empire.  If you have seen lesions like those in Fig. 2, on your trees, then you will need to protect your fruit from secondary lesions.

Fig. 2
The best product for protecting your fruit is Captan, a protectant, so that means that your trees will need to be sprayed with Captan at the full labelled rate prior to any rain event to protect your fruit.  If there are no rain events between sprays, a single protectant spray will last at least 10 days but not more than 14 days, based on the product's labeled directions.  You will need to make sure that your trees and fruit are protected prior to any rain event if when using only a protectant. But, a protectant can lose its effectivness after 2" of rain, so you also want to keep an eradicant on hand like myclobutanil, which is available as Spectracide Immunox. A protectant like Captan has to be applied prior to a rain event.  If no protection is available during the wetting event, then only an eradicant like Immunox can be applied that has a reach back of at least 48 hours.  That means that it can still have an effect on the scab pathogen for up to 48 hours after a wetting event. A good option is to actually use both a protectant and an erdicant at the same time, like Captan mixed with Immunox, which will give you both protection and eradicant action after a wetting event. 

As always, be sure to follow the label directions on any spray product you may use.   For further information on control of apple scab, refer to:

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