Evaluation of 12 Yellow Flesh Peach Cultivars for Organic Production in the Northeast

Tree Health and Vigor

Winter Survival and Bud Number and Set-By the end of 2012, none of the trees in the orchard died since planting in 2010. Winter injury which caused splitting of the bark on the southwest side of the tree was observed on 2 trees after the 2011 winter, on one Sentry and one Redhaven tree. In both causes the injured area was cut out the following spring and the trees healed completely by the time of the trunk survey in October 2012. Fruit buds per shoot were observed on pencil diameter shoots in March of 2012. From Table 1 it can be observed there is a great variation in the number of fruiting buds between the different varieties. Sentry had the lowest number of fruit buds per shoot and Gloria the highest. There are many more fruit buds on the lowest fruit bud per shoot variety such as Sentry than can be supported by a shoot as peach fruit. However, the more fruit buds available the greater the possibility for a full crop especially in a year when frost may limit a percentage of the available buds during the course of bloom as occurred in this orchard in 2012. In 2012, Sentry had no crop at harvest and Gloria had the highest percent yield at 60% after the spring frost. But, number of fruit buds per shoot and fruit set are not always correlated, PF Lucky 24B had one of the higher fruit bud numbers per shoot but had only 10% of a full crop, due to frost. Timing and duration of bloom are also important factors to final fruit set.

October Trunk Survey to Access Overall Tree Health– October 8, 2011. The trunk survey was conducted to access the overall tree health of individual trees after 2 growing seasons. The tree trunks were examined from the lower limbs to just below the ground line. The trunks were examined for trunk rots, peach tree borer, vole damage, crown gall disease, damage caused by the cultivator and any other situation that may reduce tree vitality and therefore yield and tree longevity . The most prevalent problems were vole damage and peach tree borer. Due to good tree vigor and careful correction of the problems, no peach trees in the orchard have died during the first 3 years of growth.

Sentry- The largest trees in the orchard but side branch development is limited. Some winter injury occurred during the winter of 2010 on the southwest side of the trees. The winter injury was cut out in the spring of 2011. The injured area completely healed by the fall of 2011. Weeds were a problem with some thatch around the trees that harbored voles. There was vole damage on 2% of the trees. The soil was cleared away from the vole damage just below the soil line to allow the damage to heal.

Glenglo – A smaller tree than Sentry or Redhaven. The trunks are healthy with no peach tree borers or vole damage. No problems observed.

Redhaven – The trees are large and very branched with good branch angles. Some cultivator damage on the trunks but healed over well. One tree was winter injured in 2010 which was cut out in 2011. The injured healed over well. No trunk problems were observed.

FlavrBurst- Peach tree borer was observed on a few trees at the ground line as evidenced by gum and insect frass. The borer was removed and the soil mounded in the area. Cultivator damage was healed but vole damage was observed below the soil line. It was observed that several trees had the graft union planted below the ground line. Soil was removed to expose the graft union.
FFuryPF Lucky 13- this variety is not growing well under organic cultural practices. Some leaves are discolored and there is ½ the growth that was expected. Peach tree borer infested 2 trees. The borer was removed. Cultivator damage on 2 trees had been cut out earlier and cleaned up for complete callus formation and healing. Both cultivator damaged areas were well healed.

John Boy – The trees are growing well. The trees are leaning to the west due to Hurricane Irene which occurred in 2011 with high winds and rain while there were still leaves on the tree. The trees adjusted well after the storm and the variety was one of the most productive in 2012. There were no problems observed on the trunks after 2 growing seasons and a major storm.
Summerfest- This variety grows well but has very narrow branch angles. Peach tree borer was observed on 2 trees and removed. The trunks are healthy and supporting tall trees. No other trunk problems were observed.

FFury PF17- Tree growth is good and the trunks are healthy. No problems were observed.
Bounty - The trees are growing well with healthy trunks. No peach tree borer or peach canker were observed.

FFury PF Lucky 24B- The trees have very good growth and the trees are healthy. No trunk problems were observed.

Gloria- The trees are growing well in an area where the trees must compete with grass cover that has been hard to eradicate. One tree has crown gall developing at the base of the lowest limb on the trunk. The crown gall disease is systemic so the whole tree must be removed. In 2011, the tree is growing well and being observed. If the crown gall diseased tree begins to decline, it will be removed. However, the bacteria that causes crown gall may have been released into the soil and may affect any tree that is planted in its place.

Autumnstar- The trees are growing well with some vole damage on the trunk. However, the trunks are healthy with no evidence of peach tree borer or crown gall.

Peach Variety Fall Leaf Color and Drop. Both fall leaf color and leaf drop can provide important information in timing fall organic management practices and insight into a varieties progress toward dormancy and early winter hardiness. Fruit trees in general progress toward dormancy from the shoot tip downward to the trunk. Trees that hang onto green leaves a long time into the fall may be less prepared for a sudden early freeze situation than trees that rapidly pass through leaf color changes to complete leaf drop. It is not uncommon in the Mid-Atlantic region to have relatively warm fall weather in October and November but a sudden drop in temperature to single digits for several days in early December. Another reason for monitoring leaf drop is that an early spring disease on peach leaves known as peach leaf curl is controlled by applying an organically approved copper just before dormancy when the leaves are at 90 % leaf drop. This fungus survives on the surface of twigs and is susceptible to control at this time. In 2011 leaf color and leaf drop was recorded on November 4 and leaf drop again on November 11 (Table 2). No low temperature occurred in December of 2012. Significant winter injury was also not observed after the 2012 winter. However, peach leaf curl was observed in the spring of 2012 so a copper application will be applied to manage the disease.

Peach Tree Vigor.- Tree vigor regulates tree growth, fruitfulness and fruit quality. Orchard site, variety selection and nutrition are components of tree vigor. The orchard was planted in 2010 on a virgin agricultural site that had been newly cleared in 2009 of stumps and the biggest rocks (rock removal never seems to end). The site was logged over 10 years prior to planting by the previous owner. Prior to purchase it was determined that the site had a southern exposure for maximum sunlight interception by the fruit trees, and a high elevation that permits good air drainage and air circulation. The soil is Highfield silt loam which is well suited for growing fruit trees and it has good soil water drainage.

Innate tree vigor was an important criteria for selecting varieties after disease susceptibility and harvest season. It is important to have fruit trees that grow well and don’t tend to be poor growers or become stunted in an organic orchard. It is a complex process to provide balanced nutrition to organic orchards since the fertilizers must all be natural products and normally require months to years to impact tree growth and fruitfulness. Orchard nutrition is reviewed in a later section. Table 3 provides tree height after growing season 2 (2011). It should be noted that tree height and growth is affected by fruit production. Trees that produce fruit have fewer resources for growth and therefore trees that have no fruit will normally grow more. The percent of full crop yield in 2012 is listed in Table 4. The reduced crop on all varieties was due to frost that occurred during bloom in the spring of 2012.

Suitability for Perpendicular –V Training System. This training system requires that peach varieties grow with wide limb angles that promote more light and air circulation within the canopy thus inhibiting disease and results in more red color on the fruit. Additionally the peach variety must grow multiple shoots along the main ‘V’ limbs to produce good fruiting wood and maximize yield. Several of the varieties grown in this trial grow easily into a ‘V’ canopy system. Some other varieties grow very narrow angled limbs resulting in very tight ‘V’ canopies that result in reduced light, air circulation and red fruit color. Some cultivars grow wide branch angles but produce few shoots along the ‘V’ limbs which results in reduced fruiting wood. Table 5 provides a ‘V’ training system rating for each of the cultivars grown in this trial. After 3 years of training, the varieties that are best suited in this trial to ‘V’ training include; Sentry, Redhaven, FFuryPF Lucky 13, FFury PF Lucky 24B and Gloria. Those varieties evaluated that are least suited to ‘V’ training include; Summerfest, Glenglo, FlavrBurst, FFury PF 17 and Autumnstar. As the trees mature these ratings could change. Since organic production requires cultivation and perhaps mowing close to the tree trunk, wider angled limbs off the main trunk may get in the way of working close to the trunk. Trunk damage from a cultivator did occur during this study on the wider angled ‘V’ limbs. However, the damage can also be attributed to the less than skilled use of the cultivator by the operator. Less cultivator damage occurred over time as the operator’s experience increased.

Fruitfulness/Yield/Fruit Quality. It is important the orchard produce a high percentage of clean organic fruit for the orchard to be profitable and to build markets for fruit sales. When the peach varieties were selected for this orchard the decision was made not to select varieties with the highest consumer demand but to choose varieties with low bacterial spot disease susceptibility. It is very difficult to manage this disease with available organic pest management materials. Therefore, none of the newer white flesh, low acid peaches which are very popular with consumers were selected for planting. The white flesh peaches were developed on the west coast and have high to very high bacterial spot susceptibility. During the first 3 growing seasons no bacterial spot has been observed on the leaves or fruit of any of the varieties even though the third growing season (2012) provided nearly ideal conditions for the disease early in the season. The varieties selected were also chosen to harvest fruit from early through late season (Table 6).

The first harvest for the peach orchard was in 2012 when the trees were in their 3rd leaf or 3rd growing season. Very warm weather in March 2012 pushed the bloom period earlier than is normal for this part of the Mid-Atlantic region. Peach fruit bud stage development and the percentage of buds in that stage were recorded on March 15, 18 and 25 and listed in Table 7. It becomes quickly apparent from Table 7 that bud stage development varies widely between varieties. For better or worse, a frost occurring during bloom will have a greater or lesser impact on crop loss depending on the actual stage of develop of the blossoms of each specific variety. On March 27, 2012 the temperature dropped to 27 degrees F for 4 hours according to the Davis Weather Station located next to the peach orchard. The impact of the frost on the yield of the varieties evaluated in this trial can be seen by comparing bloom stage to yield in Tables 5 and 7. However, fruit bud number per shoot (Table 1) may also play a role on frost impact on yield since fruit bud stage varies even on one variety. More buds per shoot may provide more buds in a less susceptible stage for damage by frost at any one time (Gloria).

Yield and Fruit Quality. As mentioned earlier, fruit yield on each variety was impacted by a March frost (Table 4) and by the number of fruit buds on a shoot going into the spring (Table 1). Yield is also impacted by tree growth and size (Table 5) and available water during the growing season. Adequate moisture was available for sizing fruit throughout the 2012 growing season (Table 10). No irrigation was provided during 2012. There was a 6 week period of drier weather in May and early June, 2012, but there was little negative impact on yield or fruit size. The fruit was thinned to 6 inches between fruit in May with additional fruit thinning occurring later in the summer to eliminate fruit with bird pecks or insect stings. Removing damage fruit from the tree during the growing season when it was first observed was considered to be an important component of the pest management program and maintaining fruit quality. Reducing the potential for rot diseases to spread from injured fruit to healthy fruit was considered a high priority. Orchard surveys to observe and remove damaged or rotted fruit was conducted every 2 or 3 days from just after bloom until harvest. Very few fruit (1 to 2 per tree/season) were removed due to rot. Most fruit was removed due to bird pecks, splitting at the stem end (after rain) or insect damage, before the rot got started.

Fruit harvest dates are listed in Table 6 by variety. Overall the harvest was 2 to 3 weeks earlier than the published harvest dates because of the early season.

Pest and Beneficial Insects

Early Season.-No insects were observed on the foliage of the peach trees in 2011 other than green peach aphids. The few scattered colonies were quickly eliminated by lady bird beetles. Later in October, 2011, peach tree borers were observed at the base of the trunks which is described later in this report as part of the trunk survey description.

The first pest insects observed in the peach orchard in 2012 were again green peach aphids in late April. New colonies of young aphids were scattered across the orchard with infestations higher in some of the varieties than others. No organic materials were applied to manage the aphids so that the lady bird beetles would be allowed to naturally control the aphids as occurred in 2011. By May 6, 2012 the aphid colony numbers had increased up to 20% of the shoots on some varieties but lady bird beetles had begun to appear as well (Table 8). It was interesting to note that no syphid fly larvae were observed in the aphid colonies. From experience observing aphid colonies and beneficial predators in the adjacent organic apple orchard, syrphid flies do not appear to become important to aphid control until later in the summer. Within 2 weeks young lady bird beetle larvae could be found in nearly every aphid colony that still had live aphids and by the end of May, no live aphid colonies were observed on the peach trees.

The oriental fruit moth is a serious pest to peach in the form of a worm that can infest the fruit. Since all the fruit had been removed from the second leaf peach trees in 2011, no controls for oriental fruit moth were implemented. Oriental fruit moth pheromone traps were placed in the peach and adjacent apple orchard in early June to monitor moth populations throughout the summer. Mating disruption pheromones were placed in the peach orchard, the nearby organic apple orchard and in the woods and brush at the edges of the orchard to cover 5 acres in early June. No oriental fruit moth were caught in the pheromone traps all season nor were any peach fruit infested with oriental fruit moth larvae.

Plum Curculio can damage peach fruit as they first begin to form just after bloom. Plum curculio damage had been observed on fruit in the adjacent organic apple orchard the previous season so the risk of plum curculio damage in the peaches in 2012 was a possibility. The orchard was sprayed with Surround WP just after bloom. Whether or not the Surround WP was effective is not clear but no plum curculio damage was observed on any of the green fruit during pre-harvest pest counts or at harvest.

The brown marmorated stink bug (BMSB) and the green stink bug (GSB) were observed in the peach orchard during pre-harvest scouting. Since these insects are very mobile and tend to drop off the leaf when approached their numbers in the orchard were difficult to quantify. The BMSB were observed in the peach trees in low numbers in late April to early May. No data tables are included in this report since although they could be seen at various times and trees in the orchard none were observed on tagged observation shoots during the course of scouting. Early in the season they appeared to be feeding on young peach shoots and newly forming fruit. No organic management materials were applied since the numbers of insects per tree were so low. Green stink bugs were not observed in the orchard until mid-July on John Boy fruit. Green stink bugs cause damage to the fruit known as catfacing. Catfacing damage appears as large sunken areas on the fruit surface where the stink bug has literally eaten out the surface of the fruit. From mid-July on through the summer, GSB caused as much damage to the fruit at harvest as the BMSB. Both stink bugs seemed to build in the orchard with greater occurrence and more damage to the fruit as the harvest season progressed. Organic materials for stink bug management were applied twice but whether there was any reduction in stink bug numbers or damage to the fruit is not clear. However, there was little stink bug damage on early fruit varieties. Damage to the fruit increased on mid to late season varieties (Table 9). There did not appear to be a stink bug preference for any one variety of fruit however, varieties with thicker fuzz (FFuryPF Lucky 13) did appear to have less green stink bug catfacing damage.

No other insect problems were observed during the course of regular insect scouting in the peach orchard for the duration of the 2012 summer or harvest period.

Beneficial Insects are ever present in the peach orchard. It is not difficult to find adult lady bird beetles or adult syrphid flies anytime from mid-summer into the fall, although it is not always clear what they are feeding on in the trees. Larvae of both of these beneficial are always associated with aphid colonies. Organic insecticides were not applied over the course of this 2 year project to control aphids. The beneficial insects controlled the colonies within a few weeks anytime aphids appeared. Organic insecticides were applied twice in the 2012 season for stink bugs. In August 2012, adult and immature praying mantis began to appear in the organic peach orchard and the adjacent organic apple orchard. They were not difficult to find on the plants on the ground under the trees or in the peach canopies. Their appearance seemed to be associated with the buildup of stink bugs in the orchard. During the winter months of 2013 it was observed that there are one or two praying mantis egg masses per tree. Praying mantis egg masses are also very easy to find in the brushy areas surrounding the orchard.

Wild flower areas were established next to the orchard to attract beneficial insects. In addition through the support of NRCS, a hedge of native plants was established in 2011 next to the orchard. Beneficial insects and several native pollinator insects were routinely observed in the established wild flower area and on the small hedge plants. However, the orchard is also surrounded by 60 acres of non-cultivated plants and naturally occurring perennial and annual wildflowers. An abundance of beneficial insects and native pollinators can be observed in this area from the early growing season until frost in the fall. Non-fruit tree pest aphid colonies are also commonly found in the non-cultivated area and normally support a healthy population of lady bird beetles and syrphid fly larvae. The wildflower and hedge row planting along with the large non-cultivated plant area around the peach orchard are a ready source of beneficial insects when pest insects infest the orchard.

Peach Diseases

Disease pressure in the peach orchard was light even though it was warm and wet from June through July, 2012 (Table 10). Peach leaf curl was observed on the leaves of some varieties in May 2012 (Table 11 ). Peach leaf curl infects the developing leaves early in the growing season, deforms the leaves as they grow and causes the leaf to defoliate where a new leaf must be generated by the tree in the same season. If peach leaf curl is allowed to build up in an orchard over several years it can cause significant stress to the tree and may result in tree death over the winter months. Fruit wood development and fruit growth and ripening can also be affected. In 2012, the number of infected leaves was too few to cause any real problem to the trees but it did signal that controls must be implemented prior to the 2013 growing season to stop the build-up of the disease in the orchard. Rusty spot is caused by powdery mildew and was observed on FFury PF Lucky 24B early in the season. The affected fruit were thinned off during the normal fruit thinning process with no rusty spot observed on fruit at harvest on any of the varieties. Brown rot was observed on one Gloria blossom during bloom. No brown rot was observed on the fruit on the tree during the growing season or during harvest. No other fruit or leaf diseases were observed in the orchard during the growing season. A limited number of peach cankers developed on a few trees as a result of winter injury and cultivator damage and is discussed in the October tree trunk survey.

Peach Tree Nutrition

Multiple soil samples were collected in early 2011 for nutrient analysis and sent to the Penn State University Agricultural Analytical Services Laboratory. The results indicated the pH was between 5.8 and 6.2 and recommended lime be applied at a rate of 2000 lbs per acre. The lime was purchased from a quarry and spread in December 2011. Soil samples indicated most elements were in the optimal range. However, the observation of less than idea shoot growth on the trees indicated nitrogen was needed in the orchard. After consultation with Dr. Robert Crassweller, the technical advisor on this project and a poultry manure mineral analysis, poultry manure was applied to the peach orchard that would result in a rate of 40 pounds of nitrogen per acre. The trees grew and fruited well in 2012 after the lime and nitrogen application. No nutrient deficiencies were observed in 2012. A petiole sample of the leaves of each of the varieties was collected in late summer 2012, dried and sent to the PSU Soil Analysis Lab for nutrient analysis. Most nutrients were in the normal range. On some varieties iron, zinc and copper were low, and phosphorus and magnesium were high. Besides nitrogen, the poultry manure also contributes phosphate, potash, calcium, magnesium, sulfur, copper, zinc, manganese, iron to the soil. Additional soil and leaf samples will be collected in 2013 to verify pH and nutrient levels and take steps to make changes in the levels as required.

Davis Weather Station

Having access to a weather station located at the orchard is an important component to monitoring disease risk, interpreting the impact on weather conditions and peach tree growth and productivity, and pest management. The weather station used in this study is a Davis Vantage Pro-2. It is set up next to the orchard and records changes in the weather continuously 24 hours a day. The weather information is sent wirelessly to the farm office where it can be viewed on a monitor. The monitor displays current temperature, wind speed and direction, rainfall intensity, amount of rain since midnight, humidity and leaf wetness. The data can be downloaded from the base monitor and summarized for any period of time required. Uses for a weather station include, wind speed and direction for spray application timing, rainfall amounts for residue wash off, irrigation needs and impact on insect and disease development. It would be difficult to know what is happening in the orchard without current accurate site specific weather information. Table 10 displays maximum and minimum temperatures and rainfall amounts by month for 2011 and 2012. In 2011, rainfall amounts were much lower in June, July and August than they were in 2012. The result was that in 2012, warm wet conditions existed during the fruit ripening and harvest period which can stimulate more fruit rot development. Maximum and minimum temperatures for 2011 and 2012 don’t look that different, however, the mean temperature for March 2012 is a little more than 10 degrees higher than March 2011. The higher temperature in March of 2012 is what caused early bloom, the risk for frost damage to blossoms and a reduced peach yield.

Although my experience with growing these peach varieties organically is limited (3 years growing, one year of harvest) I will discuss the varieties I believe are best suited to organic production in the northeastern U.S. My top 3 picks are; Redhaven, John Boy and Gloria. Redhaven and John Boy are old, classic varieties that have been grown for many years in the region. Gloria is a new variety so it is not well known by area fruit growers or consumers. Redhaven and Gloria are very good growing varieties, branch well for perpendicular ‘V’ training and crop well. John Boy has a little less vigor but branches and crops well. Fruit quality is excellent with all three varieties. Redhaven and John Boy crop in the mid-season. Gloria is a firm peach which some people may not like, but Gloria’s flavor is excellent, and bruising is not as big a problem as it is with peaches that are soft when ripe. I do have some concern that Gloria’s late harvest season may become a problem in the future when diseases and insects like stink bug build up potentially reducing fruit quality. My least favorite varieties are; Sentry which grows a big tree but seems to produce few fruit, Summerfest which has very narrow branch angles making perpendicular ‘V’ training difficult and Autumnstar which blooms early making it susceptible to early frost damage and ripens late when disease and insect pressure may be greater.

But, with a few more years of growing and harvesting peaches organically, I may change my choices of the best peach varieties to grow organically in the northeast U.S. I didn’t observe any major differences in disease susceptibility or insect damage between the varieties, so pest pressure was not a component in selecting the best organic varieties.

• Table 8. Green Peach Aphids and Lady Bird Beetles on Shoot Terminals, May 6, 2012

• Table 1. Average Number of Fruit Buds on Pencil Diameter Shoots
• Table 2. Leaf Color Rating and Percent Leaf Drop in Nov. 2011
• Table 3. Peach Vigor and Height at the End of the 2011 and 2012
• Table 4. Peach Yield in 2012 by Variety
• Table 5. Suitability to perpendicular V Training on 3rd leaf Peach Trees, 2012.
• Table 6. Susceptibility of Twelve Yellow Flesh Peach Cultivars to Bacterials Spot and Harvest Dates
• Table 7. Variation in Peach Flower Bud Development During 2012 Bloom
• Table 9. 2012 Fruit Damage at Harvest
• Table 10. Weather Monitoring and its Impact on Orchard Decisions
• Table 11. Ave. No. of Peach Leaf Curl Shoots per Tree
• 2nd Leaf Peach Trees, V Training
• October Snow Showing Ribbon on 2nd Leaf Trees for Counts
• Healed Peach Canker
• John Boy Fruit
• Brown Rot on fruit
• Syrphid Fly Larva Feeding on Aphids
• Sentry Peach Leaf Color at 2nd leaf
• Green Stink Bug on Peach
• Brown Marmorated Stink Bug Damage on Peach
• Gloria Fruit Pre-Harvest