May is another important month for orchard care, as this is the season when many insect pests first emerge and damage from many diseases is also first noted. Please check out our new POP Monthly Orchard Task List for recommended maintenance activities to complete this month. 
Here is some more detail on some of the key tasks for May: 

Pest and Disease Monitoring & Identification

Join us on Sat June 12, 2021 for our hands-on POPCORE 2 workshop on Eco-Orchard Pest and Disease Management!  This will be held at Bartram’s Garden and will demonstrate techniques including fruit thinning, fruit bagging, compost tea and neem oil applications, OFM mating disrupters, and beneficial insect releases.  

Spring is when many pest and disease challenges show their first signs!  Some of the most common insect pests that are likely to emerge in May include the Oriental Fruit Moth, Spotted Lanternfly, Plum Curculio, Codling Moth, and Pear Psylla

Coddling Moths can appear inside apples, pears, and walnuts. Pictured is an adult Coddling Moth (Image Credit: User AJC1, Wikimedia Commons)

Observe your orchard regularly throughout the year for pest and disease problems, identify and respond appropriately.  We’ve distributed physical copies to most community partners, but you can also check out POP’s Scouting Guides.

These guides are intended to help properly identify the insect pests and diseases that affect the following common fruit trees, including Apples, Peaches, Cherries, Plums (& Apricots), as well as Pears & Asian Pears.

The guides include lots of photos and a description of how to identify the particular pest or disease and the damage caused by it. Proper identification is essential to treating these problems, as each has its own unique options for management! Once you have identified a pest or disease, you can then consult our website for management recommendations by using our search function.

Spring Orchard Sprays 

Apply holistic orchard sprays. Holistic sprays are composed of compost tea, liquid fish/seaweed, neem oil, and/or effective microbes. For best tree health and resistance to disease, apply up to 4 times in the spring (after bud break, at first pink of flowers, after petal fall, and two weeks after petal fall). For many fruit trees, the last of these applications is due in early May. 

Depending on specific pest or disease problems, some orchardists might also consider other organic sprays including the ones listed below. In particular, plants that have suffered severe crop loss from fungal diseases (like brown rot, mildew, or scab) may be candidates for an early spring sulfur or copper spray. This is best applied shortly before or after bloom, so the time is now if you want to do this.  

Check out POP’s guides to orchard applications of:

Compost Tea Sprays for Orchards

Neem Oil Sprays

Kaolin Clay Sprays

Sulfur Sprays and Early Spring Management Techniques

Pyrethrin Orchard Sprays

Bt: Bacillus thuringiensis Orchard Sprays

Spinosad Orchard Sprays

Peach Leaf Curl is another extremely common disease in our humid climate. By the time it appears in May, it is too late to do much about it!  You can remove the affected leaves, but the only proven control measure is a copper/sulfur spray applied in late fall and/or early spring.  (Image Credit: User Eiku, Wikimedia Commons)

Spring Weeding and Compost or Mulch Application

With the wet weather and warming temperatures, early-season weeds are growing rapidly.  Time to get out there and begin editing the plant palette! POP’s weed identification guide is available for sale on our website and we always have free copies to distribute to community orchard partners. 

Building healthy soil is key to supporting trees’ health, resilience, and yields. Weed around the base of trees, and spread at least one or two inches of chipped winter prunings, shredded leaves, and/or mulch or compost in the early spring. Check out POP’s guide to Ramial Wood Chips and Weeding in Place.

Fireblight Removal and Emergency Pruning

With dormant season well behind us, most pruning should be limited to emergency pruning only.  

Keep an eye out for any diseased, damaged, or dead wood that should be pruned away no matter the season. Pay special attention to the base of trees – especially of the stone fruit varieties: apricots, peaches, plums, nectarines – and prune away root suckers, the quick upright growth that can be a cover for dreaded borers, which make a home beneath trunk wood. 

Keep an eye out for fire blight damage on apples and pears in May.  Be sure to prune back to healthy wood at least 8 to 12″ below signs of damage to prevent further spread of this disease. (Image Credit: User Ninjatacoshell, Wikimedia Commons)

Remember: use sharp, rust-free hand tools and sanitize between trees at the very least, and between every cut if the tree you’re tending has had previous conditions. For easy disinfecting, we recommend carrying a spray bottle with you of rubbing (isopropyl) alcohol or a bleach solution (1 part bleach: 10 parts water) to wipe down tools.

First Spring Harvests!

In addition to edible greens from many companion plants, the first orchard harvests are ready to pick in May. These include rhubarb, asparagus, and sometimes goumis and juneberries at the end of the month! 

Goumi berries are often the first fruit to ripen, usually at the end of May. (Image Credit: Wikimedia Commons)

17 year Cicada Alert!

POP was not in existence in 2004, the last time Periodical Cicacadas were active in Philadelphia, but apparently they can sometimes cause damage to fruit trees. Trees younger than 4 years may need protection (netting is recommended) once the cicadas emerge in a few weeks. You will know the adult cicadas are active when you hear the high-pitched whine of the male insects. You can read more about cicadas as orchard pests in this article from PSU Ag Extension.

Please report back to POP if you do see any cicada damage on your trees.

Wishing all a bountiful orchard this season!  

This POP Blog Post was written by POP Co-Executive Director Phil Forsyth, and re-edited for blog posting by POP Intern Joe Dizenhuz

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