In This Issue:
Calendar
"Stretching" the Use of Good Old Rubber Bands
Dogwood Borer (Synanthedon scitula)
Strawberry Harvest News
More Strawberry Harvest News
Fungicide Resistance: What You Should Know
Risk of Resistance Development to Fungicides Registered for Use on Fruit Crops
Fruit Observations
Ohio Apple Scab and Fire Blight Watch - SkyBit Products
Degree Day Accumulations for Selected Ohio Sites January 1, 1999 to date indicated
June 30: 1999 Ohio Fruit Growers Society Annual Summer Tour, Eshleman Fruit Farm, near the intersection of U.S. 20 and St. Rte. 101, Clyde, OH. Tour wagons begin rolling at 8:00 a.m., lunch is at noon, and annual business meeting begins at 1:00 p.m.
July 21 & 22: Small Fruit Tour, Wooster/Mt. Hope area. Pre-tour gathering begins Wednesday evening at Maurer Farms near Wooster. Included will be demonstrations of weed and disease control, strawberry renovation, drip irrigation, and raspberry plots. Dinner is compliments of the Maurers. Thursday morning the group begins its self-guided, self-driven tour at Farmers' Produce Auction in Mt. Hope. Lunch is on your own. Demonstrations at OARDC in Wooster round out the afternoon, and the day ends at Moreland Fruit Farm near Wooster with a walking tour, discussion, and fruit pies. $5.00 registration fee. For more information contact Mike Pullins at (614) 249-24424.
August 5: Young Grower Tour, northwest Ohio. Designed for, but not limited to, producers and their spouses age 40 and under. More information will follow.
We are always trying new methods and materials to help us in training trees on dwarfing rootstocks. In following our Slender Spindle and Vertical Axe training protocols, the goal is to develop branches, especially those in the Table of Production Zone (lower tier of branches), in a horizontal angle. Over the years we have tried many ideas and materials: cotton string, wire spreaders, tape, plastic, and rubber bands (elastics). Of all the materials, the one we favor is the blue rubber bands purchased from orchard suppliers. They are large bands that withstand UV light break down. After a few months in the tree, these inexpensive bands will have served their purpose and disintegrate. We have always found them to be most useful in training new succulent branches, which yield readily to the slightest pressure exerted by rubber bands. In many situations, looping two bands together to double their length makes them more effective in training branches.
The training of young sweet cherries on dwarfing rootstocks has led us to trying a new technique in making the same rubber bands even more useful and multi-faceted in purpose. The challenge in training sweet cherry branches and keeping them flat is that they are more resistant to pressure than the willowy apple branches. We are further challenged with using materials that are non-abrasive (rubber bands) to bark to avoid bacterial canker entry points. We found that when we doubled the bands and looped them together (using four bands), we could double their strength and put enough pressure on branches to orient them to the desired angle. As with the single strength bands, some follow-up adjustment may be necessary due to the effects of temperature and stress. We started applying this technique to woody apple branches with similar results. We even tried tripling the band strength and found a unique way to take two of the loops and attach them to the leader and allow four loops free to train four separate succulent branches. This latter technique will be ideal later in the summer when we begin tying apple and cherry branches down in the upper tier of canopies. We should be able to reduce tying time (labor) by having to make only one attachment point on the leader/support stake or at other points in the tree.
Give it a try and maybe you'll learn to appreciate the versatility of rubber bands in your orchard.
In recent findings at the Clarksville Horticulture Experiment Station, it has been found that mounding the rootstock shanks with sand in November 1998 has killed dogwood borer that had infested the burr knots of M9 clonal rootstocks. It is also thought that mounding right now, before egg laying occurs, will deter dogwood borer from laying eggs in burr knots.
It is suggested that growers should mound sand now over M9 and related rootstocks. By doing so, you can bypass a trunk-applied insecticide if the burr knots are covered before egg laying starts (usually late June and into July). Using a French hoe works well.
The central Ohio strawberry crop is ahead of schedule by 7 to 10 days with Earliglow being picked on May 25 and 26 with good, large, sweet berries. Cool weather has slowed the 14 day advance, but is keeping berries firm. With more warm weather projected and some replenished moisture, this crop will move fast after Memorial Day. Prices are near 1998 for pick-your-own, ranging from 75 to 95 cents per pound and from $1.75 to $2.40 per quart ready-picked.
The OSU economic analysis indicates that there is a loss of investment with 5000 pounds/acre and $.80/lb pick-your-own. This translates to a similar loss if ready-picked berries are sold at $1.55 per pound or $2.25 per quart.
In eastern Ohio the growers are more widely scattered and I am being questioned as to where people can pick strawberries. The decline in strawberry farms in that region is the major issue. The 1997 Ag census shows a decline in acreage in Ohio since 1992. I have not heard of any major replanting of strawberries taking place and would project a deficit for the next several years.
Strawberries are just starting to ripen. You can go to a 1/4 acre patch and get a few quarts, but it will still be a few days before we get into any kind of a good harvest. We did find one berry with gray mold on it. It was a patch that had been sprayed during bloom, but also one where the straw was sufficient in some spots and sparse in others. No button berries have been found, but there were a few of the ripe ones showing a little slug damage.
Continuous application of fungicides exerts selection pressure on pathogen populations. Individuals with reduced sensitivity to a particular fungicide have a selective advantage over sensitive individuals when exposed. Over time, a shift in fungicide sensitivity may occur in the entire pathogen population, resulting in diminished levels of disease control with the same amount of chemicals applied. It should be noted that diminished disease control can also be caused by improper fungicide application, extremely high disease pressure, or other factors not related to the presence of resistant pathogen strains.
Reduced fungicide sensitivity usually results from one or more mutations, which change the affinity of the chemical target site or increase inactivation or secretion of the chemical by fungal cells. Chemicals with a single-site mode of action are more likely to lead to development of resistance, since a single mutation may be all that is needed to give the pathogen a chance of survival. On the other hand, protective compounds with multi-site modes of action, such as Captan, have been used extensively for decades without development of field resistance. Resistance to sterol biosynthesis inhibitors (SBIs or SIs), which have a single-site mode of action, has been reported in Venturia inaequalis, which causes apple scab, and Uncinula necator, which causes grape powdery mildew. Diminished control of apple scab with SIs has also been observed in some Michigan apple orchards. Resistance of the apple scab pathogen to SIs has been shown at experimental sites. Last year, reduced efficacy of Nova against grape powdery mildew was observed in a vineyard in SW Michigan.
Cross-resistance refers to a situation where a pathogen with resistance to a particular fungicide also turns out to be resistant to another fungicide. This happens frequently with fungicides that share the same mode of action. For instance, a fungus strain resistant to Rubigan will also express some resistance when exposed to Nova, since both of these fungicides are SIs that affect the demethylation step in the sterol biosynthesis pathway. These fungicides are therefore termed demethylation inhibitors (DMIs). There is, however, no cross-resistance between DMIs and the morpholines, a group of sterol biosynthesis inhibitors (e.g. fenpropimorph) which act on a different step of the sterol biosynthesis pathway. No morpholines are currently registered for disease control on fruit crops.
Even though differences in efficacy will be apparent between fungicides with the same mode of action, it is generally not a good idea to alternate or mix them. Rather, devise a program which incorporates fungicides with different modes of action to optimize disease control and minimize the risk of resistance development. Resistance prevention strategies help prevent unexpected crop losses and prolong the effective lifetime of a fungicide. Fungicides registered for fruit crops are listed by group with the same mode of action in Table 1. An even better strategy is to incorporate other methods of disease control, such as host plant resistance, cultural methods, and disease prediction, to reduce the overall need for fungicides and, thereby, the selection pressure on pathogen populations.
Chemical Group |
Fungicide |
Active Ingredient |
Risk of Resistance
Development |
| Anilinopyrimidines (APs) | Vangard | cyprodinil | High |
| Benzimidazoles | Benlate | benomyl | High |
| Mertect | thiabendazole | High | |
| Topsin-M | thiophanate methyl | High | |
| Heterocyclic compounds | Captan | captan | Very low |
| Captec | captan | Very low | |
| Dithiocarbamates | Carbamate | ferbam | Very low |
| Thiram | thiram | Very low | |
| Ziram | ziram | Very low | |
| Ethylenebis-dithiocarbamates (EBDCs) | Dithane | mancozeb | Very low |
| Manzate | mancozeb | Very low | |
| Penncozeb | mancozeb | Very low | |
| Polyram | metiram | Very low | |
| Aliphatic nitrogens | Syllit | dodine | Moderate |
| Dicarboximides | Rovral | iprodione | High |
| Ronilan | vinclozolin | High | |
| Inorganics
|
Microthiol Special | sulfur | Very low |
| Wettable Sulfur | sulfur | Very low | |
| Champ | cupric hydroxide | Low | |
| Kocide | cupric hydroxide | Low | |
| Copper Sulfate | copper sulfate | Low | |
| Organophosphates | Aliette | fosetyl-Al | Low |
| Phenylamides | Ridomil | metalaxyl | High |
| Demethylation inhibitors (DMIs)
(subgroup of sterol inhibitors (SIs)) |
Bayleton | triadimefon | Moderate |
| Elite | tebuconazole | Moderate | |
| Indar | fenbuconzaole | Moderate | |
| Nova | myclobutanil | Moderate | |
| Orbit | propiconazole | Moderate | |
| Procure | triflumizole | Moderate | |
| rubigan | fenarimol | Moderate | |
| Strobilurins | Abound | azoxystrobin | Low to moderate |
| Sovran | kresoxim methyl | Low to moderate | |
| Substituted aromatics | Bravo | chlorothalonil | Very low |
| Bothran | dichloran | Moderate |
Site: Waterman Farm, Columbus
Source: Dr.Celeste Welty, OSU Extension Entomologist
Apple: 5/19 - 5/26
Peach:
Site: East District; Erie & Lorain Counties
Source: Jim Mutchler, IPM Scout
Apple: 5/19 - 5/25
Peach:
Site: West District; Huron, Ottawa, & Sandusky Counties
Source: Gene Horner, IPM Scout
Apple: 5/19 - 5/25
Peach:
Site: Wayne County
Source: Ron Becker, Program Assistant, Agriculture & IPM, OSU Extension
Apple: 5/19 - 5/26
Peach:
The codling moth trap catch in the Moreland orchard is still going up. The 250 DD since biofix was reached Monday; spraying will take place as soon as conditions permit. Pests found in low numbers were white apple leafhopper, aphids, European red mite. Fruit damaged by plum curculio is still very low. One leaf with a mine was also found the first we have found this season. Raspberries were checked in two locations with one location having one plant showing rust, the other showing about two dozen plants with rust. Wild brambles along the road show it very readily. For the most part it has been too cold to find any insect activity in fruits.
Site: Piketon Research Center, Pike County
Source: Brad Bergefurd, Ag Extension Agent, Piketon
Strawberry harvest is in full swing. Rainfalls from 0.5 to 1.5 inches were a big help for many crops. Cool evening temperatures in the high 40's have slowed down harvest somewhat. Strawberry plalnting continues. Blackbirds have been seen in the blueberry crops already. Tree fruit is enlarging quite well. No reports of severe codling moth pressure.
| Central | North Central | Eastern Highlands | North East | West | ||||||
| Date | apple scab | fire blight | apple scab | fire blight | apple scab | fire blight | apple scab | fire blight | apple scab | fire blight |
| May 8 | pi | a,ni | pi | a,ni | pi | pi | pi | a,ni | pi | a,ni |
| 9 | pi | a,ni | pi | a,ni | pi | a,ni | pi | a,ni | pi | a,ni |
| 10 | a,ni | a,ni | a,ni | na | a,ni | a,ni | a,ni | a,ni | a,ni | na |
| 11 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 12 | a,ni | na | a,ni | a,ni | a,ni | na | a,ni | na | a,ni | a,ni |
| 13 | pi | a,ni | pi | a,ni | pi | a,ni | a,ni | a,ni | a,ni | a,ni |
| 14 | pi | a,ni | pi | a,ni | pi | a,ni | pi | a,ni | a,ni | na |
| 15 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 16 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 17 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | pi | pi |
| 18 | pi | pi | pi | pi | pi | pi | pi | pi | pi | pi |
| 19 | pi | a,ni | pi | pi | pi | pi | pi | a,ni | a,ni | na |
| 20 | a,ni | na | a,ni | na | a,ni | a,ni | a,ni | a,ni | a,ni | na |
| 21 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 22 | pi | pi | pi | pi | pi | pi | pi | pi | pi | pi |
| 23 | pi | pi | pi | pi | pi | pi | pi | pi | pi | pi |
| 24 | pi | pi | pi | pi | pi | a,ni | pi | pi | pi | a,ni |
| 25 | pi | a,ni | pi | a,ni | pi | a,ni | pi | a,ni | a,ni | na |
| 26 | a,ni | a,ni | a,ni | na | a,ni | a,ni | a,ni | na | a,ni | na |
| Based on Forecasts |
| 27 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 28 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 29 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 30 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| 31 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
| June 1 | a,ni | na | a,ni | na | a,ni | na | a,ni | pi | a,ni | na |
| 2 | a,ni | na | a,ni | na | a,ni | na | a,ni | na | a,ni | na |
na = not active; a,ni = active but no infection; pi = possible infection & damage
| Actual DD Accumulations
May 26, 1999 |
Forecasted Degree Day Accumulations
June 2, 1999 | |||||
| Location | Base 43° F | Base 50° F | Base 43° F | Normal | Base 50° F | Normal |
| Akron - Canton | 750 | 378 | 916 | 871 | 495 | 470 |
| Cincinnati | 1033 | 553 | 1216 | 1272 | 687 | 742 |
| Cleveland | 747 | 376 | 913 | 828 | 493 | 444 |
| Columbus | 1005 | 555 | 1182 | 1030 | 683 | 578 |
| Dayton | 915 | 483 | 1096 | 1049 | 615 | 596 |
| Elyria | 808 | 437 | 972 | 889 | 553 | 488 |
| Fremont | 681 | 363 | 857 | 832 | 490 | 448 |
| Mansfield | 773 | 398 | 945 | 852 | 521 | 458 |
| Norwalk | 727 | 364 | 901 | 812 | 489 | 438 |
| Toledo | 756 | 391 | 926 | 801 | 512 | 431 |
| Wooster | 820 | 430 | 992 | 809 | 553 | 423 |
| Youngstown | 712 | 361 | 872 | 782 | 472 | 411 |
Phenology
| Range of Degree Day Accumulations | ||
| Coming Events | Base 43° F | Base 50° F |
| Spotted tentiform leafminer 1st flight subsides | 489-978 | 270-636 |
| Redbanded leafroller 1st flight subsides | 518-1104 | 255-658 |
| Codling moth 1st flight peak | 547-1346 | 307-824 |
| San Jose scale 1st flight peak | 581-761 | 308-449 |
| Lesser peachtree borer flight peak | 733-2330 | 392-1526 |
| Peachtree borer 1st catch | 735-1321 | 299-988 |
| European red mite summer egg hatch | 773-938 | 442-582 |
| Oriental fruit moth 1st flight subsides | 781-1574 | 442-1026 |
Thanks to Scaffolds Fruit Journal (Art Agnello)
Ted W. Gastier
Extension Agent, Agriculture
Tree Fruit Team Coordinator
Ohio State University Extension Huron County
180 Milan Avenue
Norwalk, OH 44857
Phone: (419)668-8210
FAX: (419)663-4233
E-mail: gastier.1@osu.edu
Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868