Fruit Times
Many areas of Pennsylvania farmland have been affected by the recent flooding. Since the epic rain events much of the flood waters have receded and revealed a real headache for growers. This article summarizes information from the University of Nebraska Lincoln, Texas A & M University, and Cornell University to assist in repairing fields to their original productive state.
Late summer and fall is apple harvest time. With this enjoyment of eating apples comes a new online resource about growing apples. eXtension.org, the online component of national Cooperative Extension, just added a new resource area about apple production, cultivars and rootstocks for commercial apple producers, home gardeners, nursery professionals and anyone interested in growing and eating apples.
Almost 100 crop species in the U.S. rely to some extent on honey bee pollination and the value of honey bees to U.S. agriculture is estimated to be $15 billion annually ($1.4 billion for apple). Collectively these 100 crops make up about 1/3 of the US diet and consist mainly of high-value specialty crops (i.e., fruit, vegetable and nut crops) that provide the bulk of vitamins and other nutrients that contribute to healthy diets. Honey bees are currently the most valuable pollinators in agriculture, because they are well understood, relatively easy to maintain, movable, and able to communicate rapidly the locations of new food sources. Honey bee populations, however, have declined for the past several years to the point that total reliance on them is increasingly risky. Since 2006, North American beekeepers lost approximately 1/3 of the honey bee colonies each year due to Colony Collapse Disorder (CCD) and losses at this level or higher will probably continue in the near future. These losses were in addition to declines caused by the introduction of two parasitic mite species; viral, fungal, and bacterial diseases; insecticide poisoning; and agricultural intensification of crop monocultures which have removed much of the adjacent flowering and nesting resources. Despite increased need for pollination services for crops such as the $2 billion almond industry, honey bee colonies had already declined by over 40% in the U.S. since 1947, even before CCD. Importation of bees from outside the U.S. to meet the demand for pollination began in 2005, but is a very risky solution because it greatly increases the chances of introducing new pests and pathogens to all of our bee species.
Brown marmorated stinkbug (BMSB) adults are actively feeding in apple orchards. Even blocks with already harvested fruit seem to be serving as locations to harbor migrating BMSB adults. Just before the BMSB adults will start invading all kinds of dwellings in their search for overwintering shelters, they will try to feed on any food available. And with fruit still being around, our orchards may represent the best source of available nutrients. At this moment big numbers of older BMSB nymphs (4th and 5th instar) and adults are present on soybean and corn plants as well as wild ornamental trees in the vicinity of many orchards. As we go into fall, we expect that the movement of BMSB adults and pre-overwintering intensive feeding by BMSB adults from outside hosts into orchards will become the main source of injuries of fruit. While the nymphal feeding in most orchards was effectively reduced by well-timed insecticide treatments, the feeding by continuously wandering BMSB adults is more difficult to control. With about 4 to 5 more weeks of the current growing season to go, it is extremely important that growers continue to stay vigilant and respond immediately when the pressure from incoming BMSB adults starts to increase. Although it varies for each cultivar, right now is the time for the use of the most effective options, with the shortest pre-harvest interval (PHI). Not every orchard will need special BMSB treatments but very detailed visual observations are necessary to assess the real need for these treatments. The August issue of the Fruit Times Newsletter (http://extension.psu.edu/fruit-times/news/2011/pressure-from-stink-bugs-continues-in-apple-orchards) provides suggestions for a late season stink bug control.
With about 4 to 5 more weeks of the current growing season to go, it is extremely important that growers continue to stay vigilant and respond immediately when the pressure from incoming brown marmorated stink bug (BMSB) adults starts to increase. Although it varies for each cultivar, right now is the time for the use of the most effective options, with the shortest PHI. Not every orchard will need special BMSB treatments but very detailed visual observations are necessary to assess the real need for these treatments. The August issue of the Fruit Times Newsletter (http://extension.psu.edu/fruit-times/news/2011/pressure-from-stink-bugs-continues-in-apple-orchards) provides suggestions for a late season stink bug control.
In July we couldn’t buy a drop of rain. August wasn’t too bad but September has been a real soaker—first Irene and then Lee. The eastern part of Pennsylvania was hit the hardest but nearly everyone had some rain from the two storms. Some growers are reporting support systems that collapsed under the weight of the tree and crop with all the rain. If you have some trees that went over and did not break off at the union you can rectify the problem but you must act fast. (The most recent weather forecast calls for the rain to finally end on Monday).
Our weekly observations revealed very high numbers of brown marmorated stink bug nymphs and adults feeding on soybean and corn plants in the vicinity of fruit orchards. Observations at older soybean plants (i.e., plants with pods and new beans), especially around field borders next to woods, revealed thousands of brown marmorated stink bug late nymphs and adults. Also, available traps and lures utilizing stink bug aggregation pheromone are capturing high numbers of all brown marmorated stink bug stages. Late season generations of codling moth represent a continuous challenge for all our fruit. Due to discrepancies observed between the predictive codling moth egg hatch model and the actual situation in the orchards, we strongly recommend the use of actual observations from an orchard as the main factor in deciding if and/or when the control measures are necessary. The Oriental fruit moth (OFM) continues to injure apple and peach fruit. Some loads of fruit were already rejected by local processors for the presence of live larvae in the fruit.
Fuel use is a difficult thing for orchardists to predict or manage, especially when you are looking at trying new planting systems or management schedules. As a result, it is tough to know in advance if various changes would pay off or not - especially in this era of high fuel costs.
The brown marmorated stink bug (BMSB) continues to represent an unprecedented threat to our apple crop. The incessant feeding of growing nymphs and maturing adults poses a significant economic risk to maturing fruit as each probing or feeding by BMSB eventually results in a visible injury. A single BMSB adult or nymph in the orchard can potentially cause injury to many fruit. Another complicating element is the fact that fresh injuries from stink bug feeding are initially almost undetectable, but after only a few days, the injury can become very apparent. Since their actual feeding occurs under the skin of the fruit, it is only after the affected cells start drying that the symptoms of their feeding (i.e., corking) become visible (see picture). Also, since no fungal pathogens are transmitted during BMSB feeding, the affected area remains dry and no decay is observed. If BMSB feeding occurs just prior to harvest, it is quite possible that affected fruit will exhibit no visible signs of injury, but the characteristic depression on the fruit surface will develop after a period of time in storage.
The movement of summer brown marmorated stink bug (BMSB) adults from outside hosts into orchards (or other crops) and associated deposition of new eggs slowly is becoming the most important source of new infestation in orchards. While the nymphal feeding can be reduced by effective and well-timed insecticide treatments, the feeding by continuously wandering BMSB adults is very difficult to control. With about 8 more weeks of the current growing season to go (depending on cultivar), it is extremely important that growers plan ahead with the choice of products utilized against BMSB, and preserve the most effective options, with the shortest PHI, for applications when the pressure from this pest will increase, especially in the later part of the season. The codling moth (CM) second and possibly third generation moths are actively flying in most Pennsylvania orchards. These late season generations represent a continuous challenge for all our fruit. It is still a good time to continue to control the second generations of tufted apple bud moth and obliquebanded leafroller. Although the numbers of Oriental fruit moth (OFM) observed in pheromone traps located at the Penn State Fruit Research and Extension Center continue to remain at a low level, from now on we expect to see a continuous flight of OFM. Similarly as with the CM, please use the actual local orchard observations (e.g., pheromone trap data and/or fruit injuries from earlier generation) as the main factor deciding about the necessity for OFM control.
The brown marmorated stink bug (BMSB) adults and all instar nymphs are present and actively feeding in both stone and pome fruit orchards and in surrounding vegetation. The codling moth (CM) second generation flight also is underway across Pennsylvania orchards. By the end of the first week of August it will again be time to start controlling the second generations of tufted apple bud moth and obliquebanded leafroller. Although the numbers of Oriental fruit moth (OFM) observed in pheromone traps located at the Penn State Fruit Research and Extension Center continue to remain at a very low levels, from about this time of the season we should start to observe continuous flight. The pear psylla (PP) adults, eggs and nymphs are continuously present in many pear orchards, and growers should continue to apply appropriate control measures.
Now that spotted wing drosophila has been found in Pennsylvania (see news release at http://extension.psu.edu/ipm) at low populations, the question becomes what, if anything, should growers do about it? Spotted wing drosophila (SWD), a species of fruit fly, is problematic because tiny larvae or pupae of this pest can be present in the fruit when harvested, unlike immatures of other fruit flies. We really don’t know how high populations will become in Pennsylvania, but the risk to fruit crops will likely become greater as the season goes on. In other areas of the country where this pest is already well-established, fall raspberries and blackberries have probably suffered the most damage. Blueberries and summer raspberries have also had issues though to a lesser extent, and strawberries have probably been the least affected. An additional note of caution: So far in PA, most SWD were found in small fruit plantings near cherries, the crop in which SWD was first found, so growers with cherries nearby may want to be keep an eye out for SWD. Whether this is likely to be the situation in future years or not is not known. Management options will vary by crop, and are outlined below.
Over the last month, I have seen levels of apple scab that I never imagined possible in conventionally sprayed commercial orchards. As I write this, I have just returned from seeing two commercial orchards with complete control failure. In one of the blocks where I obtained samples, an entire crop of 'Fuji' is so heavily damaged that it may not be accepted for juice.
During the last few weeks of scouting orchards, we continued to find all possible forms of brown marmorated stink bug: eggs, adults (individuals from both old overwintering and new summer generations) and all various instars of nymphs. The BMSB was observed not only in stone and pome fruit orchards but also was detected on various wild plants in surrounding vegetation. As of now, we still did not see significant BMSB population build-up on agronomic crops such as soybean or corn. Fortunately, so far (July 22), our extensive BMSB monitoring activities, which include surveying of orchards and border areas around orchards did not detect any rapid movement of BMSB populations from surrounding vegetation into orchards. Although the visual monitoring still remains the best monitoring technique, finally the currently available traps and lures utilizing another stink bug (Plautia stali) aggregation pheromone started to systematically capture BMSB nymphs (no BMSB adults in traps as of now).
Energy-efficient practices on the farm bring to mind fancy new equipment like solar panels, wind turbines, and biofuels. But you don’t have to jump head-first into buying the latest technology. With just a few simple changes to your operation, you can start to see real savings at the pump and on your electricity bill.
Skin damage has been a problem in packed stone fruit in some years but it has been somewhat erratic here in PA. The leading authority on skin damage in peaches and nectarines is Carlos Crisosto and his collaborators at UC Davis. They have been working on the problem going back into the early 1990s. Recently they have separated out two distinctive types of skin damages. One they call field inking and the other skin burning. The former occurs in the field and is visible at harvest. Skin burning is damage to the skin observed after packing and handling caused by a combination of pre- and/or post-harvest physical abrasion with exposure to high pH and/or high forced air cooling velocity. The latter disorder is somewhat cultivar dependant depending upon the skin phenolic composition. Unfortunately, since most of the work was done on varieties grown in California we do not know the susceptibility of the more common varieties grown in the mid-Atlantic region.
The movement of brown marmorated stink bug summer adults from outside hosts into orchards (or other crops) could now become a significant source of new infestation. Other insect pests to be monitoring are Japanese beetle, codling moth and Oriental fruit moth.
High populations of brown marmorated stink bugs (BMSB) are being observed in and around fruit orchards located mainly in the southern part of Pennsylvania. Also, during our monitoring of orchards that experienced high BMSB pressure last season, we have already detected BMSB injured fruit. It is assumed that most injuries visible to this point were caused by the feeding of the overwintering adults, although new, young 2nd and 3rd instar nymphs were also recently observed feeding on pome and stone fruit. With an extended spring emergence of BMSB adults, it will be impossible to clearly determine the current developmental phase for any particular local BMSB populations. As the season progresses, all developmental stages (i.e., eggs, nymphs and adults) will be present in the orchards at the same time. Additionally, the ability of this pest to survive and reproduce on almost all green plants in our environment, will contribute to a continuous influx of new individuals into orchards from the surrounding vegetation. If last season taught us anything about this pest, we have learned that stink bugs migrating from the surrounding vegetation can cause injuries to fruit throughout the entire season until mid-October.
This past winter at some of the fruit schools, I talked about the need to determine the nutrient status of your orchards through leaf analysis. Unlike vegetable crops, tree fruit and small fruit are not replanted every year and their roots are capable of absorbing nutrients any time the conditions are favorable. There is also a considerable amount of nutrient recycling. Nutrients in leaves that fall to the ground or brush that is cut from the trees and chopped in the orchard are recycled and made available again to the trees. Only a small portion of the nutrients are removed in the form of the fruit. Leaf analysis also can determine micronutrient levels in the tree. Soil tests for micronutrients are very difficult to validate.
The bi-annual Penn State Fruit Research and Extension Center Grower Field Day will be held Wednesday July 13th, 2011. The Field Day program will start at 1:00 pm and conclude with a barbecue dinner at 5:30 pm. Concurrent research and educational sessions will be held throughout the afternoon. A registration form is in the attached pdf.
