The potential for injury caused by brown marmorated stink bug adults and nymphs increased significantly during the last two weeks. It is time to start scouting for the presence of leafhoppers, especially in young orchards. Tufted apple bud moth and obliquebanded leafroller continue to be numerous in pheromone traps.
Conditions have been optimal for canker blight: leftover fire blight cankers continue to grow and bacteria move within the tree to growing areas causing shoot blight. Shoot blight is also occurring to those who experienced blossom blight, as well. Leafhoppers are active and will cause wounds in growing shoot tips, creating entry points for bacteria to enter. Pruning blighted areas and managing insects are the best methods for control.
The numbers of tufted apple bud moth and obliquebanded leafroller observed in pheromone traps in South-central Pennsylvania are similar to the numbers we observed 10 to 15 years ago, reaching over 100 moths per trap/week. Such high pest population levels require special insecticide applications targeting both leafroller species. This past week during our visual orchard monitoring we found the first eggs and nymphs of brown marmorated stink bug in commercial peach orchard. It is time to start scouting for the presence of leafhoppers, especially white apple leafhopper, potato leafhoppers and rose leafhopper.
The rainfall events experienced this season have prompted questions about the relative “rainfastness” of the insecticides used in fruit production. Precipitation can impact the performance of insecticides, but some compounds resist wash-off.
Everyone is now into their cover sprays in apples and should be applying calcium to help reduce bitter pit and corking. Cultivars prone to corking and bitter pit should receive 9 to 11 lb of actual calcium per season.
Researchers believe that long term honey bee declines are a result of a complex set of factors. The primary suspects are: poor nutrition, pesticides, pathogens/ parasites, and poor quality genetic stock. Here we will consider recent research results describing how pesticides might affect pollinators.
Up to 60 tufted apple bud moths per pheromone trap per week are being observed in orchards. Colonies of green peach aphid (on stone fruit) and spirea aphid (on stone and pome fruit) are commonly observed in fruit orchards. The presence of predators in 1 out of 5 aphid colonies may lead to successful biological control. Monitor for flagged peach tree terminals to assess efficacy of early season Oriental fruit moth treatments.
Primary scab infection is still occurring and this week will prove to be another critical period for disease management. Fire blight infections are popping up in the region and more could be expected as a result of the weather conditions. Scouting is a must this week; however, do not prune during wet weather. Conditions are also favorable for cedar apple rust, cherry leaf spot, and bacterial spot infections.
Fruit have almost completely moved out of the size range of being responsive to thinners. In looking at the fruit at Rock Springs yesterday anything small was rapidly shelling off. Fortunately, most of the fruit that was shelling off were those that had been damaged by the May 23 frost. Continue to monitor your fruit drop to see if you will need to do any follow up hand thinning. I would also suggest that you look back over the past model runs and compare the actual balances with the time you made your thinner applications.
Colonies of green peach aphid and spirea aphid are commonly observed in some orchards. Watch for predator populations such as ladybird beetles or syrphid fly larvae. The presence of predators in about one out of five aphid colonies may lead to successful biological control. As we continue to control the wide spectrum of other fruit pests, no special treatment against brown marmorated stink bug should be necessary unless nymphs are found in the orchard.
If you still have a window for thinning apples, the majority of sites in Pennsylvania show a normal carbohydrate deficit, indicating that standard chemical thinner rates can be used.
The primary infection period for apple scab continues, although available spore numbers are decreasing. Growers should be scouting for fire blight infection thanks to the ideal conditions we have been experiencing throughout the month. In light of the hail some growers experienced this week, a reminder that diseases still need to be managed despite a damaged or minimal crop during the season. Going into June, growers need to be mindful about controlling for sooty blotch and flyspeck soon.
In the Biglerville area the 2015 biofix for Oriental fruit moth (OFM) was established on April 26; spotted tentiform leafminer on April 12, codling moth on May 07, tufted apple bud moth on May 10 and obliquebanded leafroller on May 21st (Penn State Fruit Research and Extension Center [FREC] orchards). According to the insect developmental model provided by SkyBit Inc. as of May 29th the egg hatch of the first OFM generation is already completed while the first generation egg hatch periods for codling moth (CM) and tufted apple budmoth (TABM) are underway and will continue for the next few weeks.
Based on weather station data, we had only low risk fruit rot events in both Pennsylvania and Maryland up until mid-May, when several warm rains soaked the region, leading to two to three dispersal events. There are likely more to come, which means that throughout the region, there is an increased risk leading up to harvest of strawberries, and bloom time for many fruit crops. Protection of these highly susceptible flowers and fruits is critical.
When growers send in strawberry leaves for a nutrient analysis, should the petioles remain attached or be removed?
The bi-annual Penn State Fruit Research and Extension Center (FREC) Grower Field Day will be held Thursday, July 9, 2015.
A band of strong storms blew through Pennsylvania and Maryland this afternoon. If you experienced hail, apply streptomycin to apple and pear trees within 24 hrs of the hail event to prevent trauma blight. More heavy thunderstorms are in the forecast until early Thursday. Please be on alert.
This is the time of the season when next year’s flower buds are initiating and beginning to form. Your return bloom program should begin after this year’s crop becomes unresponsive to chemical thinning but before the crop becomes sensitive to the ripening effects of NAA or ethephon.
Erin Dugan recently joined Penn State Extension as Specialty Crop Innovations Program Manager and Young Grower Alliance Coordinator.
Today's carbohydrate model indicates that most sites have a low deficit and that the standard thinner rates can be reduced by 15%. The one exception is the northeastern part of the state where a high deficit is predicted for today.