Plant Lovers' Almanac: A bit about bad bugs, blight and blooms

Chaotic weather continued last week, with tornadoes and heavy rain in some locations, blistering heat and pleasing springtime weather on the weekend, the latter not so surprising, since it was technically still springtime. This week we worked our way back into the 90s heat Tuesday as summer officially arrived, though a bit cooler at the official summer solstice at 5:14 a.m.  

Oakleaf hydrangeas are in full bloom, diervilla is sporting its dainty chartreuse blooms, bottlebrush buckeye foliage and form is fine, with its spectacular panicles of frilly late June flowers soon to follow, and katsura tree foliage reaches for the sky. Welcome, summertime.  

Beautyberry

(Callicarpa).  It is months early for the other-worldly, metallic-sheened berries of this shrub, but it shares some summertime “blues” of purple clusters of flowers on the beautyberry in my backyard.

The genus has a worldwide range of species, from China to Japan, from Madagascar to Australia, and the Americas.

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Beautyberries are in the mint family and are now available in the trade with not only the more common purple fall fruits, but also salmon-pink versions, and even white beautyberries. The real show is those berries, but the flowers are lovely now.

Berries are very astringent, but with enough sugar, jelly may be made. And, the U.S. Department of Agriculture has patented a mosquito repellant from callicarpenal. 

Speaking of mosquitoes

This was part of my “bad bugs” talk at Secrest Arboretum in Wooster this week. 

Mosquitoes are clearly the worst of the worst from our perspective. Yes, females inject their piercing mouthparts beneath our skin, causing unwelcome pain and itching that mars our summertime outings. But that is the least of it; mosquitoes are considered the most damaging invasive species throughout the world, with estimated cost of $162 billion per year in damage as a vector for infectious pathogens, thought to cause over 700,000 deaths annually.  

Vectors of pathogens: Let us count the ways and means. Malaria, Zika virus, West Nile virus, chikungunya virus, dengue, yellow fever, a raft of encephalitises. These “small flies” in the Culicidae family are legion.

The most devastating pathogen vectored by mosquitoes is the parasite Plasmodium, causing malaria, vectored by Anopheles spp. mosquitoes. Malaria alone is estimated to cause 220 million cases worldwide annually, with over 400,000 deaths. 

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Dengue is an extremely common viral disease, and is vectored by another set of mosquitoes,  Aedes spp. Worldwide over 4 billion people are in areas of risk for development of dengue. Elephantiasis or lymphatic filariasis is caused by a nematode, as noted in a recent Almanac posting, and guess what, it is vectored by … mosquitoes. And on and on. 

In a 2019 book “The Mosquito: A Human History of our Most Deadly Predator,” Timothy C. Winegard details the introduction of mosquitoes to susceptible host human populations (and other animals) throughout the history of the voyages of discovery. He calls mosquitoes “the destroyer of worlds” and “the ultimate agent of historical change.” Critics have quibbled with some of his broad historical commentary, but the devastating importance of mosquitoes is undeniable.   

It's another example — among many in our COVID-saturated immediate past and present — of the fact that as big an imprint as humankind makes, it’s a tiny, tiny, world out there that often rules the day: mosquitoes and their far tinier fellow travelers, from plasmodia, to nematodes, to viruses.  

Fire blight

A friend recently called with a concern about fire blight strikes on their ornamental pear tree. Fire blight, caused by the bacterium Erwinia amylovora, is a serious disease of plants in the rose family, especially apples and pears.

Arguably fire blight is what caused the demise of the fruiting pear production industry in the early 20th century in Ohio. We have too many warm, wet days during bloom, the key environment for development of this disease. There is not much that can be done other than pruning out affected shoots, well back (like a foot) of the obvious “shepherd’s crook” symptoms.

Commercial growers use copper bactericides and sometimes streptomycin sulfate in early spring, but this is not practical or recommended for homeowners.  

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Note:  We so often think about invasive species as coming from somewhere else, forgetting that some of our native organisms invade other lands.  Erwinia amylovora is native to North America, but is a problem because of its spread to Europe.

They are more than a little concerned in China, where fire blight has not been found, especially when you consider that China produces nearly half of the world’s apples. According to the March 22 issue of the American Phytopathological Society’s journal, Plant Disease, in 2019 of the 87 million metric tons of apples produced worldwide, China produced 41 million tons, Europe 11.5 million tons and the U.S. 4.8 million tons. American as apple pie?  

Barnes Preserve

This Wooster site is the latest nature preserve my wife and I have visited in our recent quest to visit all of the preserves in the state, started during COVID distancing times. We visited this preserve once soon after it was established in 1999, so two weeks ago we decided to check it out again.

It was delightful, with Koehler’s froggy pond, meadows and woodlands.

Started by the family of Don and Dorothy Barnes, who were directors of the Wayne County Care Center, it contains nearly a mile of trails that meet the requirements of the Americans with Disabilities Act. So it is quite accessible in nearly any kind of weather. 

There are a number of park benches, including one with a bit of horticultural “irony,” at least in the Alanis Morisette — if not the literary — sense. This bench, labeled “Rest in Nature,” was under a young ash tree flush with green foliage and clusters of pale-colored ash fruits.  Alas, this ash is not long for the world, faced with the long rest that awaits us all. Though fairly healthy-looking now, the telltale D-shaped exit holes of Agrilus planipennis (emerald ash borer) on the ash trunk, peppering areas of shedding bark, spells coming doom.  

Check out Barnes Preserve for a pleasant outdoor walk, for scenes of flowering grasses, of numerous hickory trees, an ample picnic pavilion, and on a playful note, a sign at Koehler’s Pond, announcing, “Frog Parking Only: All Others Will Be Toad.”   

Jim Chatfield is a horticulture educator and professor emeritus at Ohio State University Extension. If you have questions about caring for your garden and other topics, write to chatfield.1@osu.edu or call 330-466-0270. Please include your phone number if you write.