Fruit IPM for 6/26/19

Peach:

Oriental Fruit Moth: Second generation timings are updated below. Second flight adults are still flying statewide. Treatments for the second generation have just finished in southern counties, and are going on now in northern counties.

Brown Rot: With the recent rains, sulfur should not be part of the spray program. Most growers should be relying on a captan based program for mid-season covers, followed by better materials during the last 3 weeks pre harvest.

Bacterial Spot: This disease is still present, and has increased in severity, especially in some nectarine plantings in northern counties. See previous newsletters for controls.

Apple:

Codling Moth (CM): The first generation flight has decreased and should be just about over. Some areas where the population has been high still have trap counts above 5 males per trap per week. Growers should continue to treat for this insect as long as trap counts are above the treatment threshold of 5 males per trap.

Aphids, Green apple aphid and Spirea aphid complex: Populations continue to build in some orchards. This is an insect that we can tolerate to at least when 50% of terminals infested with healthy colonies. These aphids DO NOT transmit Fire Blight or other diseases. As populations start to build, they will attract a number of predators, some of which will also feed on mites.

Wooly Apple Aphids (WAA): Aerial colonies are starting to appear in some apple orchards, particularly in northern counties. If WAA populations get out of hand, they can affect bud formation and mark fruit. WAA populations are easily seen, particularly on young trees, then treatments are justified. WAA are more difficult to control than other aphids. If done early, Movento will work. Diazinon can also work, but can only be used once post bloom.

Figure 1. Young WAA colonies on petiole bases. Photo – A. Atanassov.

Potato Leafhoppers (PLH): PLH continue to  establish in several orchards. Potato leafhoppers should not be tolerated especially in new plantings and orchards where fire blight is present as they can vector the disease. Most materials that control leafhoppers will also control aphids. These include the neonicotinoids and Sivanto. Do not use Actara, Admire or Belay if flowering weeds and clover are present in the groundcover.

Grapes

Diseases are the main concern at the present time as summer diseases become the focus.

Grape Root Borer (GRB): Root borer adults have started to emerge. Our traps only record the emergence curve, and not the presence or severity in your vineyard. Most of the adults captured in traps are coming from wild grape hosts. Survey work carried out over the past 3-4 years has shown that only 25-30% of sampled NJ vineyards have GRB populations that justify treatment, which would normally fall during early to mid-July. If you have the labor and time, clear the bases around 70-75 vines in an acre of vineyard. Then monitor for the exuvia or pupal cases left on the ground as the adult emerges (Figure 2).

Figure 2. Grape root borer pupal case left on ground after the adult emerged from the roots at the base of the grape vine. Photo – D. Polk.

This should be done once per week and for the next 6-8 weeks around the base of each marked vine. Number the vines, count the pupal cases around each vine, remove the pupal cases, and repeat the following week. Treatments are justified when at least 5% of the vines have pupal cases present on the ground.

Lorsban directed at the base of the trunk and the surrounding soil is the only effective insecticide application. However, a mating disruption system is also available and should be considered if you have GRB populations. Lorsban may not be around for too long, and a bill currently in front of the State Legislature may speed that up. So replacements like mating disruption should be explored.

Grape Trap Counts

Scouting Calendar Tree Fruit Southern Counties

The following table is intended as an aid for orchard scouting. I t should not be used to time pesticide applications. Median dates for pest events and crop phenology are displayed. These dates are compiled from observations made since 1995 in Gloucester County. Events in northern New Jersey should occur 7-10 days later.

Tree  Fruit Trap Counts – Southern Counties

Tree  Fruit Trap Counts – Northern Counties

Blueberry

WARNING! WARNING! – Spotted Wing Drosophila (SWD): Both males and females continue to be captured, and have recently increased in a number of fields. While this week has been dry, previous recent rains have made it challenging to control SWD.

• Rain has washed off recent insecticide applications.
• Soft ground has made it difficult to get in with ground sprayers.
• Duke, which may not have been picked on time, became more attractive for egg laying females, thus increasing the population that is now putting pressure on ‘Bluecrop.’
• Machine picking leaves fruit on the ground and increases the hosts on which SWD females will reproduce, thus increasing population pressure.

DO keep fresh insecticide on the fruit. Fresh means 5-7 days between applications. DO NOT keep a 7 day program going if significant rains fall just after a spray. Some growers have a 10 day schedule, and 10 days is too long an interval, especially with any rain. ‘Significant rain’ may mean as little as .5”. See John Wise’s (MSU) chart reprinted below and from the 6/13 newsletter. DO use supplemental applications if rains wash off the previous cover. DO rotate chemistries as much as possible. DO dial up your firmness sorters for firm fruit, so they kick out ANYTHING that resembles a fruit with even the slightest soft spot. SWD will make the fruit soft, and this can be detected with the sorter.

* Number of days after insecticide application that the precipitation event occurred.
Insufficient insecticide residue = Insufficient insecticide residue remains to provide significant activity on the target pest, and thus an immediate re-application is recommended.
Sufficient insecticide residue = Sufficient insecticide residue remaining to provide significant activity on the target pest, although residual activity may be reduced.

DO run 1 qt samples of unsorted fruit from every picking from every field. If a sample comes up positive for an SWD maggot, then re-run the sample from the same field and picking after it’s sorted and packed. Low numbers will be eliminated in the line if the sorters are set for firm fruit. Use the Steve VanTimmeren’s Filter Method for fruit, and outlined below. A microscope is not necessary, but a magnifier or good hand lens helps: See also Spotted Wing Drosophila IPM in Blueberries on the NE IPM website:

Use 1 qt of fruit and place in a 2 gal Ziploc bag (or into two 1 gal bags). Gently press the berries to break the skins. Add saturated salt water to cover the fruit in the bag(s), squeezing out the air to keep berries immersed, and stand the bags for about one hour in a plastic tub so they are upright. Bend a piece of ¼” hardware cloth in a large funnel, and pour the contents of the bag through the funnel into a reusable stainless steel coffee filter. Then rinse the empty bag and berries with a sprayer to wash off any remaining larvae into the stainless steel coffee filter. Use a strong hand lens or a dissecting microscope to count the larvae caught in the coffee filter. This method is detailed in: Van Timmerman, S., Diepenbrock, L.M., Bertone, M.A., Burrack, H.J., Isaacs, R. 2017. A filter method for improved monitoring of Drosophila suzukii (Diptera: Drosophilidae) larvae in fruit. Journal of Integrated Pest Management. 8(1):23; 1–7.

¹ = Use a 10-15 day PHI for berries going to Canada.

Blueberry Maggot (BBM): Most blueberry maggot trap captures are “0”, but a few traps do register low populations. One trap at an unsprayed location had up to 8 flies per trap. Remember that the treatment threshold is 1 fly per trap. Just about ALL the insecticides that are being used for SWD control are also excellent for controlling BBM, with the lone exception of Delegate/Entrust, which is still OK, but only on low populations.

Scale: Scale presence on fruit has decreased this past week, indicating an end to the first crawler generation. We had an average of .09% of fruit with scale. Make sure to record those fields where you see scale on the fruit coming into your packing house. These fields should be treated during the 1^st week of August, or when we see the second generation crawlers emerge.

 Aphids: Aphid infestations have slightly increased since the previous newsletter, possibly owing to recent rains and vigorous shoot growth. The average level of shoot infestation was 2.28% of shoots infested with a maximum of 52% of shoots infested. Colony size has also increased to2-5 aphids per shoot. This is important, since we saw a number of fields with Scorch symptoms several weeks ago. These plant should be removed. Where aphids have increased, especially in the presence of Scorch, separate additional applications of aphicides may be needed. The neonics – Admire, Assail and Actara; and Sivanto and Movento Do Not control SWD at this time of year.

 Oriental Beetle (OB): Oriental beetle adult emergence is well underway. The population is in the middle of laying eggs, which will hatch into young larvae that burrow down to feed on blueberry roots. Now that ‘Duke’ and other early varieties are mostly off, you have until the middle of July to get the Admire treatments on if not already done so. Of course if you have the mating disruption dispensers out, then you don’t have to worry.

Anthracnose: Some low levels of anthracnose have been seen in the field and in the cull trays on the packing lines. The average field infestation was .04% of fruit infected with visible symptoms, with a maximum of just over 1%. This has not been a year to go easy on the fungicide sprays. Bluecrop in coming on, and it is even more susceptible than Duke to this disease, and most anthracnose is expressed after harvest and not while still in the field.

Blueberry Traps

Atlantic County Traps

Burlington County Traps