Back to top

Healthy Fruit 2009 Vol. 17:13

Jul 7, 2009

Current (through July 6) degree day (DD) accumulations

Location: UMass Cold Spring Orchard (CSO), Belchertown, MA

  • Base 43: 1484
  • Base 50: 898
  • Note: this will be the last degree-day update for 2009

Significant upcoming orchard events based on degree days (Base 43):

  • obliquebanded leafroller summer larvae hatch: 1038–1460
  • oriental fruit moth 2nd flight begins: 1275–1489
  • oriental fruit moth 2nd flight peak: 1468–1948
  • spotted tentiform leafminer 2nd flight peak: 1382–1796
  • apple maggot 1st catch: 1228–1620

The way I see it

I hope you plan on attending the Massachusetts Fruit Growers' Association Summer Meeting at Tougas Family Farm on July 15. It should be a great, all-day outdoors program featuring sprayer calibration exercises, sweet cherry hi-tunnels, self-propelled platform, netting options for cherries and blueberries, young bench-grafted apple tree planting, and containerized apple and blueberry nursery. Pre-register for the meeting today, and/or click here for program details.

Otherwise, I contend it is a bit of a lull right now with the exception of sweet cherries -- we are at the end of sweet and tart cherry harvest @ Belchertown, with Regina and Balaton just coming in as late-maturing cherries. Cracking and splitting has been significant with all the wet weather we have had. One year it is the birds, one year it is frost, the next it is cracking and splitting. There is little doubt in my mind that you must grow sweet cherries under some kind of rain cover, i.e. high-tunnel, Haygrove, etc. I will say, as I have in the past, Balaton is a real 'sweet' tart cherry. It will still make you pucker, but has been our most reliable cropper since 2001 when the cherry orchard was planted at the UMass Orchard. They are easy to harvest -- stemless -- and given the purported antioxidant properties of tart cherries, and the interest in locally grown, they should be a real winner at any market. Please plant on dwarfing Gisela rootstocks and you will not be disappointed in Balaton.

What else is new? Not much -- just apple maggot, calcium sprays, hand-thinning of peaches and apples, watch brown rot as peaches ripen (like, starting in 2 weeks?), potato leafhopper, Japanese beetles, summer disease control sprays in apples.

The next Healthy Fruit will be published on or about July 21.

J. Clements

This and that from everywhere

As I write this Tuesday afternoon, while watching the live MJ Memorial on CNN.com, I have the luxury of reviewing several newsletters from other sources. Thus, to not re-invent the wheel, I am going to 'borrow' from several sources what I find interesting coming off the wire. Hope it works for you too. J. Clements

Apple Maggot (AM): The threshold for AM fly is 5 adult flies per baited red sticky trap. Since June 22, an average of 2 flies per trap in Highland so treatment is not needed at this time. In 2008, we achieved threshold by the 14th of July. Early varieties such as Ginger Gold are most attractive to AM with later maturing varieties more attractive later in the season. Blocks of early varieties should have insecticides applied shortly after threshold is reached. Assail, Calypso, organophosphates, carbamates or pyrethroids used for OFM management will reduce the early AM adult populations. Cornell Cooperative Extension Hudson Valley Research Laboratory, Tree Fruit Recorded Message for Tuesday, July 7, 2009.

June Bug; Japanese Beetle: June bugs and Japanese beetles have been flying for about a week. These insects can be troublesome on ripening fruit and usually peak around Redhaven season. Provado @ 6-8 ozs.acre (0 day PHI), Assail (70WP) @ 2.3-3.4 oz/A (7 day PHI), and Sevin (4F) @ 2 qt/A (3 day PHI) are suggested for control. If you are using Assail, you may still see Japanese Beetles immediately after application, but they will have stopped feeding and will die after a few days. Rutgers Plant & Pest Advisory, Fruit Edition, July 7, 2009.

Brown Rot: As peaches ripen and start producing more sugars, they become extremely susceptible to brown rot -- fungicides should be applied starting about 3 weeks before expected harvest. Indar, Orbit/Tilt, Elite, and Pristine are all highly effective brown rot materials. Take a conservative approach, given the extreme amount of moisture we've had this year! Polaris Orchard IPM Newsletter, Observations and Opinions from the Field, July 7, 2009.

Stink Bugs: Stinkbug injury on apples has been observed in some apple orchards over the past few years. Orchards at risk for injury are usually those located next to wooded areas or hay fields. Injury often occurs on hot days during mid to late summer or when haying operations are occurring. If using Intrepid, Rimon, Altacor, or Belt for CM control, include an OP or carbamate for stinkbug control, or switch to a more broad-spectrum material if you are in an area likely to experience damage. (Ed. note, watch for stink bug damage in peaches too.) Rutgers Plant & Pest Advisory, Fruit Edition, July 7, 2009.

Obliquebanded Leafroller: This is a good time to scout terminals and clustered fruit for leafroller larvae. Most of the larvae I have seen so far are on terminals, and have begun to create shelters by rolling leaves together. If larvae are seen and no treatment has been applied yet, Altacor or Delegate or possibly Rimon would probably be the best course of action at this relatively late date. Include a spreader to let the material distribute into sheltered areas. Polaris Orchard IPM Newsletter, Observations and Opinions from the Field, July 7, 2009.

Oriental Fruit moth (OFM): Hatch of the larva was predicted to occur on the 1st of July. In Highland we observed trap threshold of the 2nd generation OFM adults on the 29th of June with more than 10 moths/trap/week captured. About 50-60% of the eggs laid by this generation have already hatched. If trap thresholds were not exceeded at the beginning of 2nd flight, a single spray for this generation can be applied this week. The management timing for OFM this season coincided with the 2nd application for OBLR. The residual of Delegate and Proclaim will have excellent efficacy against both OFM and OBLR populations. The pyrethroids, Bt's, Intrepid, Leverage, and Lannate are all effective against the OFM. High summer temperatures have been reported to reduce the effectiveness of the pyrethroid class of insecticides. In orchards that have a history of previous fruit infestation from this pest, populations may be resistant to organophosphates or pyrethroids. In these instances, Assail, Avaunt, Calypso and Intrepid may be used for resistant populations. These materials are timed earlier then the organophosphates carbamates, pyrethroids and Avaunt, with applications to begin early this week. Cornell Cooperative Extension Hudson Valley Regional Fruit Program, Tree Fruit Recorded Message for Tuesday, July 7, 2009.

Guest Article

Reprinted from: Scaffolds Fruit Journal, Vol. 18 No. 16, July 6, 2009

Art Agnellow, Editor

COME WHAT MITE: SOME GUIDING PRINCIPLES OF MITE MANAGEMENT

Art Agnello, Entomology, Geneva

Now that we are entering another mite control season, it doesn't hurt to quickly go over some basics for maximizing the effectiveness of the tools we have for keeping them under control. Mite management can be considered to be a 2- phase process: 1) An early season program, against

the overwintering generation; and 2) A summer program, directed against new populations.

Usually, a preventive approach (i.e., without the need to sample) is advised for early season, depending on the previous year's pressure. Among the options available for this task are: delayed dormant oil, an ovicide-larvacide (Apollo/Savey/ Onager/Zeal) applied prebloom or (adding Agri-Mek to the list) after petal fall. For summer populations, scouting and sampling is advised to pick up rapid mite increases on new foliage, especially during early summer, when trees are most susceptible. During this phase, thresholds increase as the summer goes on and the trees become more tolerant of mite feeding. When the numbers of motiles (everything but eggs) reach or approach threshold, a "rescue" material can be recommended, among them are: Acramite, Apollo, Carzol, Kanemite, Nexter, Onager, Portal, Savey, Vendex, and Zeal.

Because mites have many generations per year, they have a high potential to develop resistance. Some major differences between resistance management programs for fungicides vs. insecticides and miticides are:

  1. Insect and mite resistance is not promoted by using low dosages of materials; i.e., it doesn't cause a populations shift in their susceptibility, as can occur with pathogens.
  2. Frequent applications of high rates usually will not prevent or slow down the development of insect and mite resistance.
  3. Usually, high dosages are not toxic to resistant insects or mites, but they do kill a greater number of susceptible individuals.

Recall that resistant mites are theoretically "less fit" or weaker than susceptible individuals. They have shorter lives, are physically smaller or weaker, produce fewer offspring, take longer to develop, and their mating success is lower. In the absence of competition from susceptible individuals, resistant pests rapidly multiply.

The key to management of resistance to insecticides and miticides is to reduce selection pressure that favors the survival of resistant individuals. Some tactics for doing this are:

• Treat different generations with materials of different chemical classes.

• Use nonchemical control tactics where possible (e.g., biological control by encouraging predators).

• Use good miticide stewardship: apply only when necessary; use correct dosages; obtain adequate coverage; and optimize your timing.

Back in 1992, our miticide choices were not very numerous: oil, Morestan (prebloom), Vydate,

Omite, Carzol, and Kelthane. We have many more options today, but it's important to keep in mind how they may (OR may not) differ:

  • [1A] Carzol: carbamate; acetylcholinesterase inhibitor
  • [12B] Vendex: disrupts ATP formation
  • [6] Agri-Mek: GABA (neurotransmitter) site; affects chlorine ion channel; inhibits nerve transmissions
  • [25] Acramite: GABA (neurotransmitter) site (probably); contact activity
  • [10A] Apollo/Savey/Onager: growth inhibitors
  • [10B] Zeal: growth inhibitor
  • [20B] Kanemite: METI (mitochondrial electron transport inhibitor), Site II
  • [21] Nexter/Portal: METI (mitochondrial electron transport inhibitor), Site I

These numbers are assigned by IRAC (Insecticide Resistance Action Committee), which is an international organization of researchers and scientists committed to prolonging the effectiveness of pesticides at risk for resistance development. The number codes represent Mode of Action Classifi cation Groups. An arthropod population is more likely to exhibit cross-resistance to materials within the same group.

For more information on this effort, see: http://www.irac-online.org/

Timely and updated fact sheet available on the UMass Fruit Advisor website

F-119R Foliar Calcium Sprays for Apples

Summary recommendation for using foliar calcium sprays to reduce the incidence of cork spot and bitter pit

  • Begin 3 weeks after petal fall
  • Apply every 2 weeks until harvest
  • Use 0.6 to 0.8 lb calcium (2 lb calcium chloride) per 100 gallons dilute until mid-July
  • Use 0.8 to 1.0 lb calcium (3 lb calcium chloride) per 100 gallons dilute after mid-July
  • If using calcium chloride, add 2/3 oz vinegar per lb calcium chloride, use a surfactant, avoid Solubor or epsom salts, avoid spraying when very hot, and foliar injury may increase if used with Guthion or Captan
  • See the fact sheet noted above for more precautions and details