Weird Insects - Part 1 - Introduction & Hiders

For reference, I am a plant pathologist by training.  This means that the focus of a good chunk of my studies has been centred on organism or factors that cause disease, whether a bacterium, fungus or perhaps an abiotic (non-living) process.  Despite my tendency towards all things rotting, in my work over the past decade I have developed a fascination for unusual insects.  More often, it is the strange things that they do to plants to hide or protect themselves or as they feed that catches my eye.

Introduction

Insects can do an incredible amount of damage to plants.  Some insects eat specific layers of cells, or suck the juices out of plant parts or do whatever they do best to eat and thrive.  Some insects just sit out in the open and feed, in some cases consuming foliage at an amazing rate.  This sort of damage is fairly obvious.  Other insects are more subtle (or wise, that is debatable), preferring to create shelters to protect them while they feed, grow and develop.   Some choose something in between.

What is really neat is that sometimes the insects (or insect-like pests) that cause the biggest, most obvious injury or damage symptoms are actually tiny immature insects.  What follows is a rogues’ gallery of some of the interesting insects that I’ve come across over the past few years.  I’ll try to break them into sections of similar actions or similar species.  Since I am not an entomologist (a.k.a. Bug guy), my groupings may offend those with more training or education.  Too bad, so sad.  In this, I’m in it for the entertainment value.  In some cases, some of the insects that I share with you could fit into several categories.

Hiders

Lots of insects go to great lengths to conceal or protect themselves from harm during development and end up producing are some wild symptoms.

Maple Leafcutter (Paraclemensia acerifoliella)

This insect has a history in other regions of causing a fair bit of damage to maples.  In Alberta, there wasn’t really a record of it until a few years ago, when it was discovered on an entirely different species, Saskatoon berry (Amelanchier alnifolia).  This insect skeletonizes (feeds on the surface leaf tissues) from underneath a shield that it creates from two pieces of leaf.  As the larva develops, it has to replace the shield with a bigger one.  The feeding damage is unique and the shield sticks out, however, you do have to dig and peel to expose this critter.

Maple leafcutter - shielded insect

Maple Leafcutter - shielded insect under cover, preparing to cut a new shield (lower left); previously cut out leaf tissue evident (lower right)

Shielded insect revealed within 2 layers of leaf shields

Meadow Spittle Bug (Philaenus spumarius)

This little critter creates a froth of its own spit to hide within, feeding on the plant.  The froth is pretty gross, but overall the damage created isn’t severe.

Meadow Spittle Bug - spittle mass on the stem of a weed

Meadow Spittle Bug - spittle mass on a strawberry leaf

Meadow Spittle Bug nymph

Pine Needle Scale (Chionaspis pinifoliae)

In some cases, insects create their own shelter from their own materials.  In the case of the Pine Needle Scale, which affects spruce, pine and firs, the coverage is a bit of waxy armour that is excreted by the females as they sort of suction cup themselves to the needles, remaining there for the duration of their lives, as they lay eggs underneath them.  The presence of scales resembles what I’ve seen described as “paint splatter”.  The crawlers (the immature form) emerge to move briefly before settling in to feed on the needles (they pierce and suck).

Pine needle scale - "paint splatter" symptom

Closer view of Pine Needle Scale insects on srpuce needles.  The black specks are the emergence holes of the "crawlers" (immature stage)

Pine Needle Scales - white spots are the female scale insects that have attached themselves to the needle to feed, lay eggs and protect the eggs and young crawlers

Leafminers (range of species)

There are many different leafmining insects out there.  These insects lay their eggs into the cellular layers between the outer epidermal layers and the larvae feed and grow with this improvised pocket until they are ready to chew a hole and drop to the ground to finish their development over winter.  Some leafminers chew channels or tunnels, other just go to town within the entire area, as is evident with the Birch leafminer



Birch leafminer - note the pockets that form from feeding on the tissue layers underneat the epidermis and cuticle, as well as the frass (poop) that is visible as dark brown/black powder in the lower parts of the bubble

Another type of leafminer, this time on willow.  The feeding is more like tunnels rather than an enlarged pocket

Birch leafminer on Cutleaf Weeping Birch - tan brown areas are indicative of feeding and infestation; occasionally, in younger infestations, the larva will be visible moving around in the pocket

Simple tips for keeping diseases at bay

Every year, gardeners lose produce, sleep, hair and have their general happiness eroded through the onslaught of a range of diseases that sicken their plants and undermine their efforts to create a beautiful and productive yard and garden.

When it comes to diseases, there are three basic requirements in order for disease to occur.  Without all three, you won't get disease.  The level of each combines to create the overall severity of the disease.  The first is a susceptible host.  The second is a pathogen.  The third are conditions that favour the development of the disease.

While you can’t always fix every problem, there are a few things that you can do to try and minimize the impact due to disease.

• Start clean – It is critical to start with the best plant material that you can.  Just because something is cheap doesn’t mean you should purchase and plant it.  Select plants that are healthy, free from disease, and that are actively growing (if that is what you want).  At the same time, make sure that the location that you have selected is good enough to give the plants a chance to get established and give them a head start on any attackers.  The same conditions will help the plant stay ahead of any attacks (hopefully). 
•  Accept defeat (temporarily) – Some diseases will come back year after year and some diseases have very specific hosts.  If you get a disease that needs a certain host, consider not growing that plant for a couple of years, or if you have the space, don’t plant in that location.  It might mean sacrificing the taste of a favourite veggie for a short time, but in the long run, breaking the disease cycle will hopefully mean fewer headaches in the long run. 
• Don’t over water or overfeed – It is possible to kill with kindness, especially in the garden.  Don’t succumb to the temptation to keep throwing water and fertilizer at the plants. Healthy plants are more resistant to disease (generally), whereas plant gluttons are lush, soft and overgrown: a.k.a. easy targets. 
• Drainage – Plants generally aren’t adapted to growing in water and react accordingly when subjected to saturated or overly moist conditions.  Too much water will usually result in poor, weak growth and an increase in both root rots and other diseases.  Over watering can actually look like the early stages of drought stress, but there is no nighttime recovery or positive response to adding more water. 
•  Let the air flow – Stagnant air or poor air flow results in higher humidity and the potential for more foliar diseases.  Don’t put plants too close together, either in beds, between or within rows.  Ensure that perennials are pruned properly and don’t create a completely enclosed, over-sheltered environment. 
• Encourage drying – Most diseases thrive in moist conditions.  The longer leaves and plants stay wet, the easier and more quickly diseases can develop.  Consider watering in the morning, when plants will dry out more quickly.  Consider watering the soil surface, not the foliage. 
•  Notice and rogue (remove) the rogues – If something looks weird or abnormal, take a closer look and see what is going on.  Consider taking anything that is abnormal OUT, in case it spreads to other plants. 
•  Remove and bury – Another way to break the disease cycle it to get rid of infected material.  If something is aggressively moving through a planting, do your best to contain it.  When the season is done, encourage a rapid breakdown of the diseased material by burying it or removing it entirely from the site.

These few steps can help keep the diseases at bay and maybe cut down on the mental trauma that can come from gardening.  Good luck.

Meadow Spittle Bugs

There are literally thousands of things that surround us on a daily basis that we walk past without a second glance (or often even a first one).  However, if something is brought to our attention, we tend to notice them over and over, even if we’ve never seen them before.

Many insect and diseases are like that.  One afternoon last week, I got an email from someone asking if I knew if people were noticing a particular pest in their strawberries.  It is a very minor pest, which I’d heard of but had never set eyes on before.  Imagine my surprise (and delight, I will admit to it) when the very next morning, as I was weeding my flower bed, I came across this very insect.  Within an hour, I found it again and again in my strawberries.  It makes picking strawberries that much more interesting, since I am “eager” (yeah, I’ll admit to that), in a weird way, to find this little critter again.

Spittle mass on Creeping Bellflower (weed)

So, let me share with you this little insect that is the “proud” possessor of a fairly disgusting reputation but is, in fact, pretty fascinating.  The insect that I am referring to is the Meadow Spittle Bug.

The Meadow Spittle Bug (Philaenus spumarius) is found a number of different host plants, such as strawberry, clover, alfalfa, a number of grasses, various weeds and some ornamental plant species and is generally considered to be a minor nuisance pest in Alberta.  It is lists about 400 plant species as hosts and is considered to be a general feeder.  It can be damaging in some regions and on some crops, but not on the Canadian Prairies.

Most likely you’ll find (and recognize) MSB more by touch than sight most of the time and, odds are, MSB will be there but you won’t see it.

Frothy spittle "gift"

The first (and predominant) sign of spittle bugs is a subtle-ish frothy or foam mass on the stems, leaves, or perhaps the fruit of the host plant.  Spittle masses can range in size, but are often upwards of ½ an inch or more in diameter.  In my experience, masses can be found pretty much anywhere in the plant canopy but are most often in the lower parts of the canopy.  As you move strawberry leaves aside to find and pick the fruit, you’ll get a wet/slimy feeling and find your fingers with a bit of wetness or foam on them.  Not overly pleasant, but bearable.  You might also catch a glimpse of a mass on an upper leaf surface.

Spittle mass on upper leaf surface of a strawberry

Closer view of spittle bug mass - note individual bubbles

Spittle bugs feed by piercing and sucking.  MSBs don’t tend to cause yellowing, but if there are lots and lots of spittle bugs on the plant, you might see some stunting or perhaps wilting of the plant.

MSBs look a bit like large aphids (a bit egg or pear-shaped), but adults are mottled and winged and can hop and fly (aphids just sort of mosey slowly or park, for the most part).  They are approximately 7 mm in length.  The nymphs are what you will find inside the spittle mass.  They range from orange-yellow to green (depending on the instar (growth stage)) and can stay inside the masses for up to a month while they mature.  Unlike aphids, they can really move when they are motivated.

Spittle bug nymph (probably later instar)

Spittle bug nymph (side view)

MSBs overwinter as egg masses that are laid on lower plant parts.  Nymphs hatch and emerge in late spring.  Once the nymphs hatch they start feeding and produce a frothy mass of little bubbles.  After close examination, I can safely say that they essentially blow the bubbles out of their nether regions, which extends to look a little like a short elephant trunk that waves back and forth, side to side, depositing a bubble one at a time.  In a short time (2-3 minutes), they can produce enough bubbles to equal half their body size.  The spittle masses protect the MSB nymphs from predators and desiccation.

Meadow Spittle Bug nymph - note the slightly distended rear end (where the bubbles come from)

Spittle bug nymph blowing bubbles out of its nether regions

Some sources lead me to believe that spittle bugs are more of an issue in humid regions, which would suggest that MSB might be more of an issue in more humid years.  It certainly jives with the tendency of the MSBs to put their spittle masses in the lower canopy, where the humidity is higher.

While the MSB is gross (people hate to put a hand in the masses), it generally doesn’t merit any sort of control measures.  Weedy areas/fields tend to have more MSBs, so controlling weeds can cut down on hosts and keep populations to a minimum.  Chemical applications (if they are made) for other pests may coincidentally control the MSB, however the spittle masses also protect the nymphs for the most part.

While I am not an “insect guy”, you have to admit that insects can be pretty interesting.  So, keep an eye open.

Dealing with insects in the garden

There are literally hundreds or thousands of different insects that find their way in and through our gardens every year.  Some are there all the time, some just come and go.  Most are harmless to you and your plants and lots are even helpful.  Encouraging them is worth the effort.  Some insects (the pests) are annoying.  Some are destructive and have a significant impact.  Managing them is a challenge.  Regardless, we first have to accept that insects are there (whether we like it or not) and from there we can move to minimizing the impact of the pests.

What follows is a brief and simplified list of some the things that you might consider doing (alone or in combination) to minimize the overall impact of pests, by reducing or preventing infestations and making things less “pest-friendly”.

• Start clean – Insect pests can, and will, arrive under their own power.  Some walk.  Some crawl.  Lots fly.  Others catch a ride.  However, bringing them into your garden seems a bit foolish and is a bit like tempting fate.  It is kind of like saying “They probably won’t like it here”.  Therefore, the strategy is to ensure that any plants that you introduce to your garden are free from insects or other pests.  Give the plants you are buying a good once-over and pick those without any stowaways.  Also, make sure that any plant material that you plant is healthy, so they have a good head start on life. 

•  Know your friends – There are many (a huge number) beneficial insects running, flying or crawling through the garden.  Try to understand what the insects that are present are doing.  Recognize the insects that that aren’t doing any damage or that might be helping out.  Just because it is on the plant, doesn’t mean it is hurting it.  Some good insects may resemble the bad ones, but you can often tell friend from foe using the statement in the Bible that said “Wherefore by their fruits, ye shall know them.”  Watch what they are doing. You’ll see the clues.

• Know (and understand) your foe – Just like knowing your friends is important, you have to be aware of the different pests that can damage your plants (a.k.a. your enemies).  Know that what they and their damage looks like, as well as a bit about their life cycle.  This way, you can know whether you have a problem or not and how best to minimize their impact.  The idea is to know what their Achilles heel is and where to hit them.  By knowing how they move, how they overwinter, how they reproduce, if they need specific hosts, what climatic conditions they prefer, you’ll be better equipped to counter them.

• Encourage rivalries – Once you know friend from foe, you should consider encouraging and/or introducing beneficial insects as a way to manage the problem insects.  You can do this by being judicious in your pesticide applications, planting species that serve as a “home” for the beneficial insects and implement practices that encourage them to stay.  Sometimes you have to sacrifice a bit of quality and a small pest problem to keep your beneficial alive and productive.

·         Exclusion – Some plants can be protected by keeping the pests off.  Essentially, you tolerate them in the neighbourhood, but you don’t let them live on your plants.  It is important to understand the habits and life cycles of the pests you might encounter.  Depending on the pest, you might protect using plant covers, short mesh screens (for those insects that are low flying), barriers around the base of the plants or other means of keeping insects from either feeding on or laying their eggs on or around the host plant.

• Lure and trap the scoundrels – If you can’t beat them in a direct and fair fight, trick them, then destroy them.  Many insects are drawn to plants by detecting the unique chemical “odours” put out by the plants.  Others are drawn by colour or other triggers.  Use this natural habit to your advantage.  Try the following:

o   Putt out trap plants – these plants serve as sacrificial lambs, which you either drop the bomb on or that you remove once they are loaded (or they just load up on the pests, while the plants you actually like pass unscathed.

o   Place sticky traps - these yellow or blue cards are meant for monitoring, but they catch a fair number of pests, as a side benefit.  They are simple, cheap and just need a bit of sticky stuff to be effective.  Their orientation relative to the ground and their height relative to the canopy will determine what you catch.  Change them when they start to fill up.

o   Place baits (liquid or solid) – these are geared to drawing the pests to where you can either remove them or kill them.  Some people use shallow pans of a beverage or maybe a partially buried piece of potato, depending on the pest.  You might need to change or “recharge” them occasionally, if they are popular.

• Remove and destroy – Some pests are big enough or occur in dense enough populations that you can pick them up and remove them (and perhaps the plant part that they are on) easily.  Anything that you can do to interrupt their life cycle and cut down the population, the better off you’ll be.  This method ties in nicely to trap plants or baits.  In lots of cases, you need to go after either eggs, adults, nymphs or other immature stages, such as larvae.  I still remember the Great Potato Beetle Hunt of ’85, where a bounty was offered for adults and larvae in a jar and for crushed egg groups. What I don't remember is being paid...

The overall message is that you can have healthy, good quality plants in your yard and garden.  You just have to take steps to accept, encourage, recognize and exclude and with some mental and physical exertion, you should make out fine.