Thursday, June 22, 2017

Harlequin Bug

By Stephanie Rukowicz

The harlequin bug is a type of stink bug, much more colorful than the brown ones you might find around your house. An invasive species, it is a common insect pest of crucifers in the southern part of the U.S. but in recent years has been reported in PA as well.

2016 brought my first encounter with harlequin bugs. First eggs were sighted on kale around the same time I was noticing leaf miner damage to spinach and beet leaves (early May). At the time, I wasn’t sure what had laid the eggs, but noted their distinguished geometrical grouping and pattern.
 Uncapped (already hatched) eggs.

Side view of eggs, note black striping along side.
As the season progressed,the harlequin bugs made themselves known. Mostly laying on and inhabiting my kale plants, I attempted hand control by picking eggs and both adult and baby bugs, which helped but did not eliminate the population. I noticed as I pulled and destroyed severely infested plants that bugs and eggs could also be found on closely neighboring tomato plants. The warmer winter of 2015/2016 may have played a role in my new familiarity with this insect pest. Also, two plots in our garden use a radish cover crop, possibly providing a nice winter home for adult bugs.
Harlequin bugs on the underside of a collard leaf. Adult top left, youth middle right.
Later this season, I also spotted Harlequin bugs in the Parks and Rec vegetable garden at Columbus Square Park. Is this a new issue for South Philly? I wonder what next year’s gardening season will be like and if we need a more concentrated effort to control this pest population.

Collard leaf with damage from harlequin bugs,
browning and spotting. Also showing
concurrent damage from cabbage lopers
(holes and munching around leaf margins).
“Early in the season populations and damage are often low and you may be tempted to ignore them. But, with two to three generations in a season, by the time fall crops begin to mature their numbers may be one hundred times as high, causing serious damage. Harlequin bugs reproduce quickly, developing from an egg to an adult in about 48 days. Adult males may live up to 25 days and females up to 41 days. During their adulthood they can mate repeatedly laying multiple egg masses of 12 eggs every 3 days. That means a single female can produce 164 eggs. My advice – don’t ignore harlequins bugs; put together a plan to keep their numbers low.”

“Host-free periods without brassicas can help limit the population. Remember brassica cover crops, like forage radish, are known hosts. Harlequin can also feed and reproduce on wild weedy mustards (Shepherd’s purse, wild mustard, pepperweed), pigweed (Amaranthus spp.), lambsquarter (Chenopodium spp.). Keeping these weeds under control in fields and on field edges will limit habitat. Leftover crop residue in the field provides a protected host area for over-wintering adult harlequins. Remove or disk in residue to destroy overwintering sites. Trap crops have been recommended, but I would suggest that you need to rapidly kill the bugs in the trap crop, or destroy the trap crop and follow it with a host-free period, for this to work well. Plant an early crop of horseradish, mustard or kale and try to kill the harlequin bugs concentrated on this favorite host. One grower has successfully controlled harlequin by frequent vacuuming.”

Thursday, June 15, 2017

Window Box Idea: Succulents!

By Stephanie Rukowicz

Unlike some other Master Gardeners, I have not yet developed a knack for ornamental containers. Philadelphia's hot summers, long dry periods, and our home's south facing location add up to annual die-off of most of my window box plantings. The shallow, narrow boxes just don't retain enough water to cope with the elements. Short of an auto-drip watering system, I was running out of ideas until I stumbled past this window box on one of my walks. 

Succulents! The perfect plant to withstand the urban summer elements. Now I just need to decide which varieties to try, as there are so many to choose from. 

This article from Penn State Extension is helpful in narrowing down the options. An excerpt:
"Besides their eye-catching appeal, succulents are relatively pest and maintenance free. They are easy to grow if their cultural needs are met. Their large, fleshy leaves store moisture, making them relatively drought tolerant. The larger the leaves on the plants the longer they can go without water. The most critical aspect of success with succulents is to plant them in a container mix that drains freely...Variegated and light green leaves can scorch in full sun. Darker green and burgundy leaves can generally tolerate more sun."

Sunday, June 11, 2017

Questions from the Philadelphia Master Gardener Hort Line/Ergot or not

Those of us who volunteer for the Philadelphia Master Gardener Hort Line have researched and answered some interesting questions. We have learned about plants, pests, disease, and general gardening along the way. From time to time, we'd like to share some of the more unusual and interesting of those questions with you.

Ergot or Not?

Last summer, a woman sent an email inquiry to the Hort Line that included photos of a dark growth on ornamental grass. The grass was planted in the Pennypack Ecological Restoration Trust in Huntingdon Valley. She noticed the growth as she walked the acres of trails and saw that the growth was widespread. She was concerned that it was ergot, which could pose a serious public health threat.

What is ergot? Ergot is the name given to a group of fungi of the genus Claviceps. Its most common host is rye, although it can grow on many other types of grasses, including wheat. Because we consume so much wheat flour, contamination of wheat has the most serious and wide-spread implications for human health.

Ergot causes constriction of blood vessels and has been used medically to slow blood flow from wounds and childbirth.  Unfortunately, it can also have devastating effects if ingested in excess. Ergot can cause severe pain in arms and legs, a syndrome called St Anthony's Fire.

In high levels, ergot can cause hallucinations. LSD is derived from ergot and some historians think ergot poisoning may have played a role in the Salem witch trials or other significant outbreaks of hysteria.
And it's not only humans who are affected by ergot. Livestock can become ill, as well as wildlife and pets.

So it makes sense that there are strict regulations for the presence and levels of ergot in cereal grasses. Ergot-contaminated wheat can be cleaned, but it is costly and not always successful. In some cases the wheat must be destroyed.

The grasses in Pennypack Ecological Restoration Trust were not meant for consumption, but if this was ergot, we needed to alert the folks in charge of the meadow to be sure the infection didn't spread.

My first step was to look at the submitted photos and compare them to online photos of ergot posted by the USDA and various US university extension services.

First, take a look at the submitted photos:

Now check out photos of ergot:

The good news: They don't look like the same growth, do they? The Pennypack growth is round and covered with ripples and convolutions, while the ergot is elongated and horn-shaped.

I wrote back to our questioner to say I thought it wasn't ergot, but that I wanted to be sure, I forwarded the question to Dr. Gary Bergstrom, a wheat pathologist at Cornell, who told us it was definitely a smut fungus and not ergot. I was happy to be able to report to our questioner that the growth was not a health threat. 

Another successful Hort Line investigation comes to an end!

If YOU have any questions and are not sure where to turn, ask the Hort Line! If we don't know the answer, we know someone who does!

Ask the Hort Line!

Ask the Master Gardener Hort Line 
for expert advice on all of your gardening questions!

Master Gardener volunteers are trained and have access to information on all sorts of gardening questions. 

 Weird-looking bugs in your roses? Ask us!

 Need advice on your kale crop?
                                Ask us! 

If WE don't know the answers to your questions, we know someone who DOES! 

In the words of one of our dedicated volunteers, we are in relentless pursuit of the right information!

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