Of the bugs in our lives.
It is an indictment of our air of separation from nature that we are so marooned from understanding what insects do for us, as well as the ties that bind us to them.
– Oliver Milman, The Insect Crisis
One bridge I aim to build is a short, solid path from entomology lab to kitchen cupboard. From biological controls in agriculture to familiarity with bugs in early childhood education, the public is in dire need of a reintroduction to the myriad invertebrates shaping and informing our world.
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Apples to apples:
IPM in fruit crops for the good of all.
One of the positive notes to resonate from the Pandemic was a renewed appreciation for our food producers. To cement that recognition, we ought to take a step further. We can get to know the challenges and solutions at play in sharing a workplace with countless, minute associates – some of them productive collaborators; others more disgruntled.
Integrated pest management (IPM) is an effective, practical approach to mitigating damage done by insects. It comprises a range of best practices that bear the grower, consumer and environment in mind with prevention as its first resort and chemical application as its last.
IPM in fruit crops feels like a place to start.
At a time when the public is introduced to species like spotted lanternfly and instructed to kill, kill, kill – it helps to take a step back and process what damage is being done, by whom, and what it all means. It also helps to sample a slice of what farmers are up against, when we’re troubled by the availability, pricing and quality of those goods which do make it to the aisles.
What’s in a benefit:
Understanding the good and the bad.
Who’s-who among bugs deemed “beneficial” versus “invasive”.
Biological pest control, parasitoids, and yet another case for agroforestry systems.
Circumstances, justifications, research & trends.
The Usual Suspects
Atop the mounting crises associated with climate variability, fruit growers take on a slew of insect threats throughout the seasons. Nearly every growth stage of their crop faces vulnerability to a growth stage of their invaders.
Why should consumers bother with this knowledge?
Comprehending the luxury of an aisle full of impeccable fruit, just how much didn’t make it to that aisle, and why, could help to manage consumer expectations and garner compassion, if not support, for our producers.
Apple Maggot Fly (Rhagoletis pomonella)
Apple maggot flies and their larvae are a major threat to apples in the Eastern U.S. as well as other orchard fruit regions, though their damage is not always detected immediately. Internally, the boring caused by maggots leaves browning, inward-winding paths; a heavy infestation of earlier fruit varieties will appear as rotten brown masses.
Cultural control: Monitoring for- and removing infested apples and abandoned apple trees in the vicinity. Maggots in the apples may also be killed off while in cold storage at 32°F for a period of 40 days.
IPM: Parasitoid wasps may attack on eggs and larvae, but apple maggots’ tendency to burrow within the fruit reduces the efficacy of these agents’ assistance. Careful monitoring of the emergence and dispersal of the flies and use of sticky traps can be used to time treatments. Seek out local extension or state recommendations for best practices.
Apple Tree Borers (Saperda candida +)
Saperda candida is just one of many borers drawn to fruit trees (apples, cherries, peaches, plums). They emerge post-petal fall to lay eggs throughout the summer months, after which larvae tunnel through the tree generally closer to its base. Producing a reddish frass, a heavy infestation also leaves a tree looking sickly with pale, sparse foliage. Worst scenarios or continued perennial infestations will weaken or kill a tree, especially younger trees which may give their all with a generous bloom only to die off in the effort of bringing the fruit to maturity.
IPM: Clear out alternative hosts, neglected trees and weeds surrounding your targeted fruit trees. Mosquito netting at the base of trunks can also stave off egg laying. If necessary, insecticide can be applied to the trunk for similar prevention in early to midsummer.
Brown Marmorated Stink Bug “BMSB” (Halyomorpha halys)
You may have seen them around the house; no threat to us, but notorious among crops including apples, peaches and citrus fruits. At worst, they cause “cat-facing” among orchard fruits, distorting them with puckering and scarring.
Biological control: Many generalist pests (mantids, spiders, assassin bugs, beetles, lady bugs, earwigs) feed on BMSB, so consider keeping them around.
Orchard crop IPM: Pyramid traps using pheromones effective for low populations, holding off on incorporation of insecticides until later in the season.
Codling Moth (Cydia pomonella)
Major foe of apples and pears, especially in eastern U.S. Its larvae cause both shallow and deep entry damage, burrowing into the fruit. Both types render the crop unmarketable.
Biological control: Though yet to be adopted on a commercial scale, beneficial nematodes as with the Carpocapsae-System have proven effective, efficient and environmentally sustainable.
IPM: Pheromone disruption has proven effective, as well as kaolin clay and selective viruses. In the summer, broad-spectrum insecticides may be used in conjunction with degree-day development models for greater precision and efficacy.
Leafrollers (Platynota flavedana & Platynota idaeusalis)
Tufted Apple Bud Moth and Variegated Leafroller, among others, can be found in the same orchard and produce two generations per year, with the second causing greater damage. Reasons may include developed resistance to sprays, insufficient or stopped sprays or tightly clustered fruit.
IPM: Clear apple root suckers and suppress broadleaf weed ground cover surrounding the trees. Integrate pheromone traps and a degree-day developmental model to time sprays against larvae, beginning after fruit thinning and then in late summer.
Plum Curculio (Conotrachelus nenuphar)
Chances are you haven’t come face-to-face, though you may have seen this one’s handiwork while apple picking. Unlike many insects brought over from abroad, this weevil is a Rocky Mountain native. Hard, speckled lumps are the first indicators of damage, with internally damaged fruit often dropping from the branch. They can devastate a harvest.
IPM: As of yet there are few organic approaches to staving off plum curculio beyond jarring those spotted, but precision application of sprays using degree-day models and acting during egg-laying season/petal fall can be an effective preventative measure.
Rosy Apple Aphid (Dysaphis plantaginea)
(RAA) is known to be one of the most destructive to apples, especially in the Southeast U.S. Causing the signature leaf curling on trees, their infestations can cause fruit spurs to produce an underdeveloped, misshapen and certainly unmarketable crop.
Biological control: RAA has many natural enemies, though they might not be discovered by these until after damage is done to the incoming fruit in its earlier stages. That said, lady beetles, lacewings, soldier beetles and others are important predators and in-season sprays of RAA can risk killing these key assets, allowing aphid numbers to rise.
IPM: Aphid infestations among apples don’t occur every year and RAA spend their time on other host plants like ribgrass, so take care to keep your cover crops and surrounding areas clear of these weeds and other potential hosts.
Spongy Moth, formerly “Gypsy Moth” (Lymantria dispar)
Early instars are black and only a quarter-inch long, but spongy moth larvae develop into distinct red and blue spotted caterpillars sprouting hairs all along their bodies and can reach up to 2-3 inches long. While they favor oaks, some of their top suitable hosts include apple trees and unmanaged outbreaks can turn from minimal leaf damage full on defoliation. Adult moths – the male a brownish grey and the females white and flightless – do not feed and only live for a few days, within which they mate and lay eggs.
IPM: One method is Btk management, a spray certified by the Organic Materials Review Institute whose formulation employs Bacillus thuringiensis, a native bacterium found among soil and plants. It poses less risk to animals and other non-target organisms than do conventional chemical sprays.
Tarnished Plant Bug / Apple-Lygus Bug (Lygus lineolaris)
The feeding of Tarnished Plant Bugs (TPB) on the tight cluster stage of apple development often results in aborted fruit. Later stage feedings may result in scarring, and early damage can eventually result in sunken areas and light corky russeting.
Cultural/Bio control: Remove wild or unmanaged trees in the surrounding areas to reduce populations, along with any broadleaf weeds. Hold off mowing from bloom through petal fall to prevent adults flying into trees. Preserve natural enemies (other true bugs, ladybugs, spiders, parasitic wasps).
Woolly Aphid (Eriosoma lanigerum)
Sap-suckers whose honeydew (sugary secretions/bug poop) emerge as a waxy white covering not unlike cotton or wool. Their honeydew causes sooty mold which then leads to a blackening or russetting on fruit and all parts of the tree.
Biological control: Encourage and protect natural parasitoids (parasitic wasps, lacewings, ladybugs, hoverflies, earwigs).
IPM: Planting with resistant rootstocks. Early monitoring among pruning scars beginning in early summer. Use of selective aphicides, if necessary.
At the end of the day, your best bet is still to contact your local Extension office for well-researched, region-specific advice catered to your particular crop, zone and issue. Every state – and many counties – have an Extension office more than willing to share knowledge and resources whether you are a farmer, gardener or concerned/interested individual.
Quick links to some of the sources I’ve drawn from for deeper dives below. You can also find your state’s Extension site with a simple Google search and discover no shortage of helpful links from there.
Michigan State University / MSU Extension
Spongy Moth Life Cycle – Integrated Pest Management
Btk: One Management Option for Spongy Moth
PennState Extension / Fruit Pests and Diseases
Brown Marmorated Stink Bug
Rutgers / New Jersey Agricultural Experiment Station (NJAES)
Fruit Integrated Pest Management Program
Commodity Specific Definitions for IPM in Fruit Crops in NJ – Apple
2021/2022 New Jersey Commercial Tree Fruit Production Guide – (p.115-132)
Plant & Pest Advisory – Rutgers Cooperative Extension
University of Massachusetts Amherst / UMass Extension Fruit Program
Fruit IPM Fact Sheet Series
Utah State University Extension / Utah Pests
Fact Sheets – Tree Fruit Insects
Washington State University / WSU Comprehensive Tree Fruit Site
Orchard Pest Management broken down by species
The Fly Trap – Fredrik Sjöberg
For an entomologist, fifteen square kilometers is a whole world, a planet of its own. Not like a fairytale you read to the kids again and again until they know it by heart. Nor like a universe or a microcosm, similes I’m not willing to accept. But like a planet, neither more or less, but with many white patches.
The Insect Crisis – Oliver Milman
The tragedy lies in wasted opportunities, of treatments being ripped away before we even knew we had them in our grasp. The unseen loss of insects, the sort of centinelan extinctions that cofound our understanding of exactly what we’ve banished from the living world, means we may have carelessly burned through revolutionary medicines via the mundanities of farming, urban developing and other staples of modern life. “If we lose species without finding what those uses might be, we deprive ourselves of options we might have […] We’ll never know.”
Never Home Alone – Rob Dunn
Chance does indeed favor the prepared mind, but it favors the obsessed mind even more. Obsession comes to scientists naturally enough. It emerges when one mixes focus and relentless curiosity. It can strike anyone.
Super Fly – Jonathan Balcombe
Flies have been loitering in our midst for as long as there have been humans with midsts to loiter in. The first fly on a wall surely eavesdropped in a cave.
Recommended podcast episodes breaking down IPM.
Click the titles or icons to tune in to a range of free, accessible podcast interviews coming at IPM from every angle.
A chat with Dr. Messelink, Special Professor in Biological Pest Control, who conducts research using predators and parasitic wasps to manage common pests in greenhouse production. […]
“In this episode, [Dr. Ridland] walks us through 6 broad methods of IPM and gives us a number of real-world examples of strategies that have worked in his experience working with all sorts of pests, especially those of the insect variety which are his specialty.” […]
“Brian Spencer was trained as a molecular biologist, but he found his way to biological pest control and never left. This episode [is] a conversation with Brian, who has devoted his career to mastering the control of bad bugs with good ones. This conversation is one of my favourites of this series, and will be of interest to everyone, not just the pest-obsessed.” […]
All hands on deck.
Long story short: iNaturalist.
But plenty more elaboration coming just around the bend on how to educate ourselves and those around us, casually contributing to scientific research in a real and tangible way, becoming more in tune to the world around us and delighting in small wonders.