Recently in Aphids 2009-2011 Category

During the summers of 2011 and 2012, I conducted a survey of aphid infestation in a section of the main experimental plot to track, among other things, seasonal changes in the distribution and abundance of Aphis echinaceae on Echinacea. With help from members of team Echinacea, I conducted 6 bi-weekly surveys in 2011 and 3 monthly surveys in 2012. In both years there was a sharp rise and fall in the frequency of aphid infestation. The plot below shows the percentage of plants in the survey area observed to have 1 or more aphids on each dates. In 2011, the peak of aphid infestation (i.e. when the highest percentage of plants hosted aphids) was around August 12th. In 2012, the peak date of aphid infestation occurred some time between July 13th and August 9th. I was not able to observe the peak directly due to a sudden die-off of aphids before my third survey. I estimated the peak frequency of aphids as the percentage of plants with live or dead aphids on August 10th (indicated by the asterix and x-error bar).

aphidSurveyPhenology.jpeg


I was also able to get a sense of aphid phenology from my aphid addition/exclusion experiment. In 2011 and 2012, I added or excluded aphids from 100 plants that were not flowering in 2011. The graph below shows the mean abundance of aphids in each experimental group over the summer of 2012:

treatmentPhenology2012.jpg

Based on this graph, I estimate that the peak of aphid infestation for 2012 occurred around July 22nd (202 days after January 1st), about two weeks before last year's peak.

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Like their hosts, Echinacea aphids exhibit a strong seasonality. There's a sharp rise in the frequency and abundance of aphid infestation followed by a rapid decline in early fall. That decline has occurred much earlier this year than last year. Fortunately, that has given me a chance to make some observations about what happens to aphids at the end of the summer. Here are a few things I've noticed:

1. Throughout my surveys in CG1 and several prairie remnants, I've noticed that the frequency of winged morphs has declined since July. Last week, I did not see any winged aphids, with the exception of a couple at East Elk Lake Road. This implies that dispersal declines as aphid numbers drop.

2. I and several others have noticed that aphids are starting to congregate at the base of the plant both at the petioles and at the base of the stem. I've also seen aphids crawling down beneath the soil surface and a few latched onto the tops of roots. One possibility is that as plants withdraw resources from their leaves, aphids move down the plant to follow their food source. I've also seen ants moving aphids at the base of the plant and placing them in dirt structures. These observations support the notion that aphids overwinter on Echinacea roots.

Many aphid species in temperate regions spend the winter and summer on different plants. Their winter host is where they lay eggs and their summer host is where they feed and reproduce asexually. My guess is that Aphis echinaceae does not have a separate winter host.

This plant at Nessman's had a bunch of aphids congregated at the base. Notice the little green guys on the stem:
IMG_2102.JPG

This is one of the plants from my aphid addition/exclusion experiment in CG1. There are still aphids on the leaves, but most of them have moved to the petioles:

IMG_2111.JPG

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I don't know if I've properly introduced myself on here.

My name is Katherine Muller and I'm a second year Master's student at Northwestern. I hail from the lovely, temperate San Francisco Bay Area. I'm not sure whether it was my thirst for adventure or my contrarian nature that led me to the Midwest--first to Oberlin College in Ohio, then to Northwestern and Minnesota. In any case, I now have the privilege of complaining about the weather.

This is my second year with the Echinacea Project. Last year I began research on aphids and ants in Echinacea angustifolia. I have two projects that I plan to continue this summer:

My first project is an experiment examining the effects of aphid infestation on Echinacea. Last year, I selected 100 non-flowering Echinacea, excluded aphids from 50 plants and added aphids to the other 50. I am repeating the experiment on the same plants. I performed my first experimental treatments on Saturday and Sunday and should soon be able to analyze my results from last year.

The other project I plan to continue this year is a survey of aphids and ants in a large experimental common garden. Last year I selected a 20x20m section of the experimental plot and led a biweekly of ants and aphids. I started this because I was interested in seeing how aphids spread over space and time. This year I will examine the same area to see how aphid infestation changes from year to year. Thanks to everyone's help, I collected my first dataset on June 15th. Considering the unusually warm winter, there should be some interesting developments this year.

My third project is to assess aphid and ant abundance among several Echinacea populations. My original plan was to survey aphids and ants on a representative sample of the entire population, including juvenile and non-flowering plants. As it so happens, Amy Dykstra and Daniel Rath conducted a similar survey in 2009 (you can read about it in the archives). For all their hard work, they found very few plants with aphids. Of the plants they surveyed--flowering plants had a much higher rate of aphid infestation than non-flowering plants--32% for flowering versus 5% for non-flowering plants. I decided to take a different approach and focus my sampling effort on flowering plants. Specifically, I will survey aphid and ant abundance on plants that flowered this year and last year. This will allow me to assess whether flowering in one year influences the likelihood of aphid infestation the following year.

That's about it for now. I'll be posting my progress on here as it happens. This summer I have the privilege of collaborating with Jill Gall, an REU student from College of the Atlantic. She's been hard at work preparing her project assessing ant diversity in prairie remnants, which I'll let her tell you about.

And because everyone else is doing it, here's a picture:

DSC02790.JPG

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Last summer I conducted a biweekly survey of aphids and ants in the common garden, an experimental prairie restoration containing Echinacea from various remnant populations. I was interested in the spatial distribution of aphids and ants within and across years. This year I plan to scale down my survey to once a month, beginning next Friday. Here's a detailed protocol:

Common Garden Aphid Survey Protocol 2012.doc

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I couldn't make the Midwest Ecology and Evolution Conference, but I made a poster. It describes preliminary results from an aphid addition/exclusion experiment I conducted in the summer of 2011. Specifically, it examines the question of whether aphid infestation influences the presence of leaf damage by other herbivores.

MEECPosterKMullerFinal.pdf

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It's been a busy week for everybody. Plants are blooming, pollen is shedding, and everyone is dashing about madly to catch the field season before it passes us by. I have been running around like a chicken with its head cut off trying to get ready for my aphid addition/exclusion experiment. Everyone has been a wonderful help setting up cages in this sweltering heat. My goal for this week is to finish my first round of experimental treatments: exclusion on Thursday and addition on Friday. Before then, I need to finish setting up nets and teach everyone how to wrangle aphids. Here is a protocol I wrote up to assist the teaching process and the data sheets I mention in the protocol. These are works in progress, so any feedback is appreciated.

AphidExclusionCollectionProtocol2011.doc

aphidexclusion.xls

aphidcollectionoutsideExpt.xls

aphidinfestation.xls
Happy wrangling,

Katherine

View image

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I made some updates to my project proposal. You can read them here:

link

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Today we surveyed a patch of the common garden for aphid infestation. I chose my survey area based on observations I made Wednesday morning, during my initial search for aphids. I wanted my square to include at least one heavily-infested plant with ant domatia (dirt structures that ants build to cultivate aphids). Otherwise my choice of positions and rows was random.

Here is a description of today's survey. This weekend I will go over the data and make a map of aphid infestation. Because it's still early in the season for aphids, I hope to repeat this survey one or more times this summer to look for spatial and temporal patterns of infestation. Thank you to the Echinacea team members for your diligent data gathering.

Aphid survey protocol 1June2001.doc

I'm happy to say the survey went smoothly. Everyone seemed to have an easy time recognizing aphid life stages and ant domatia. My only goof-up was accidentally assigning the same row to two people, leaving us one row short, but thankfully we caught it in time to finish up before a thunderstorm hit. Next time I will be more careful about my row assignments.

I would like to repeat this survey several times throughout the summer--maybe once every two weeks. Here are some thoughts I have based on my observations in the common garden:

1. We have observed that plants with heavy infestations early in the season tend to have wrinkly, stunted leaves--possibly due to aphid overwintering. I suspect that these plants may serve as aphid source populations that spread to surrounding host plants. It will be interesting to see whether aphid infestation is more prevalent among plants nearby heavy aphid infestations (i.e. plants with all three aphid life stages, wrinkly leaves, and ant domatia).

2. I noticed that on plants with small infestations, ants seemed to be carrying away gravid females. Perhaps ants play a role in mitigating population-wide aphid infestation by concentrating aphids on a few heavily-infested plants. This survey won't tell me much about the role of ants, but I am curious to see whether some plants lose their aphids throughout the season.

Thanks again everyone for helping me gather my first data set!

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Here is a more detailed project proposal. This one focuses on what I want to accomplish this summer:

https://docs.google.com/document/d/1PqYExtOCkmHzcLkLP3bS04_4X9OlVSZ5pjSZEiV-xp4/edit?hl=en_US&authkey=COLOz7cO

Please let me know if the link doesn't work.

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Here's a draft of two barplots that Hillary asked me to whip up using R magic. I'll let her explain what they mean.

barplots.png

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Let's take a closer look at our small, squishable friend Aphis echinaceae:


Aphid35.jpg

aren't they precious little instars?!

Aphid12.jpg

Aphid31.jpg

Aphid33.jpg

Feel free to admire this beauteous winged alate

Aphid43.jpg

This madam is so mature that she looks like Jabba the Hutt. Note the honeydew she is secreting. That bubble of delicious sugary goodness is why ants farm aphids.

There is a cool ventral shot of Jabba that the flog won't let me load up for some reason or another. Perhaps I shall try again at a later date. Until then, enjoy (it's only taken me a month to get them up)!!!

Hillary

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AphiddatasheetR.csv

I think I ought to enter a competition for who can post essentially the same data set on the flog the greatest number of times.

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AphiddatasheetRready.csv

Stuart--

Here is my aphid data ready for R tomorrow!

Hillary

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Aphiddatasheetcorrected.csv

This is the CVS file of my aphid data after making a couple of crucial corrections. Stuart, if you would insert this into the R script that shows the graphs of the population changes on each plant, that would be wonderful!

-Hillary

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This R script, hillaryLookAtAphids.r, allows one to view graphs of growth of aphid clones in Lauren and Hillary's experiment.

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Here is our aphid data, synthesized into one large worksheet and ready to be analyzed!

Love,
Hillary (and Lauren's spirit)

Aphiddatasheet.csv

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aphidrawdata.csv

aphiddatastarted.csv

Here is our data so far. We are now working on transferring the raw data into the final form!

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helandechfinaldataset3.csvAs all of you know katie and I are leaving this weekend to go back up to CBG, and I am hoping that Echinacea will be just about done flowering at all of my sites by then. It is looking hopeful and today I had my first site that was done flowering! I still need to tag the Echinacea at some of my sites though. I finished entering most of my data this weekend, and am very excited to see what the graphs and analysis will reveal. I am posting the cvs files for Stuart below, and some pics of a very interesting bug katie found today
P1010558.JPGThumbnail image for P1010560.JPG
corandcardfinaldataset2.csv
helandechfinaldataset2.csv

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In case we need help :)

Materials:
Visor
Petri dish
paintbrush
mesh bags
twist ties
a partner!

1. Sync visor, get randomized plant (row and position) from Hillary.
2. Collect aphids from several plants in Common Garden. Find leaves with fat, dark aphids (aka mature). Gently disturb aphids with brush tip. When aphids start to scurry (remove stylets), brush them gently into the petri dish. Do not mash them by rubbing paintbrush against the plastic (attempting to dislodge them).
3. When approximately 20 mature aphids have been collected (not including tiny green ones), find assigned plant.
4. Check transfer plant for ants and aphids and record presence in form.
5. Find a suitable leaf (close to ground and small enough to fit in bag) that is free of any ants and aphids (if there are no empty leaves, squish present aphids).
6. Prepare bag over most of the leaf (opening bag and pulling over leaf). Then lift the bag up enough to stick the aphids in.
7. Transfer two random aphids to the top of the leaf (one big aphid and one slightly smaller). It works best if one partner holds the leaf and bag and the other transfers the aphids. Then the bag holder pulls the bag down and the transferrer twists the tie.
8. Pull bag completely over leaf and gently twist tie it closed. Avoid strangling the leaf or squishing or dislodging the aphids.
9. If aphids take a death plunge or fall off make sure they are not in the bag and transfer additional aphids as needed.

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It's been quite a while so there is lots of good news on the aphid front! First of all, aphid casualties have decreased substantially thanks to improved transfer methods. We have now been using a paint brush to gently disturb and brush the aphids into a petri dish (upon the suggestion of Dr. George E Heimpel). This is far less traumatizing for the aphids and survival has skyrocketed from 20% to around 50%!
Also, fortunately for us, apparently all aphids at this time of the year are gravid, so we only need to select mature individuals for transferring. This was an exciting discovery since we spent a while with a microscope trying to figure out which ones were gravid before this revelation. We also officially decided to use two founders for each transfer to improve chances of survival.
Hillary and I are looking forward to checking out the preliminary data soon!

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So the weekend is upon us, summer is already beginning to slip away, and aphid abundance is on the rise.

Mine and Lauren's aphid specialization experiment is still being tweaked to perfection. We set up 5 preliminary aphid transfers on B genotype plants (the offspring of between site echinacea crosses) in order to practice appropriate aphid transfer methods and make sure that we can get aphid establishment on plants that we know aphids are found on (aka to ensure that our transfer methods do not result in aphid squashing and death). This proved perhaps more difficult than expected. I single-handedly destroyed the greater part of several aphid colonies before determining that trying to remove aphids from their leafy homes with a tooth pick was just not going to work. Eventually I settled on disturbing the leaf/gently poking at one aphid (which, it turns out, causes some species of aphid to release an alarm pheromone so all the other aphids on the leaf stop sucking phloem, withdraw their stylets and start moving around). Apparently many Aphis species do not have this alarm pheromone, but when I starting messing with the aphids/the aphids' leaf they started running around in frantic disarray, so whether or not they release a pheromone, poking them seems to work. After instigating a mass aphid exodus, I attempted to herd several confused individuals onto the flat side of a twist tie. This was also more difficult than you might expect it to be, and was rather time consuming. When we set up our actual experiment we will knock the disturbed aphids into a petri dish, which will be a much more efficient method and will probably result in a significantly less aphid mortality.

We had initially planned on using a single alate (winged) aphid as our population founder, because these are the individuals that would colonize new plants. However, this particular aphid morphology is not nearly as common as the apterous aphids (lacking wings). After conferring with Dave Andow, an entomologist from the U of M, we determined that using apterous aphids is fine, as we are testing plant suitability rather than aphid preference (ie CAN aphids colonize a certain plant, not which plant would a aphid PREFER. And anyway, preference will probably manifest itself somewhat in the form of population success and growth rate). We also discussed the important question of one founder aphid or two. If we can have lots of replicates we could have only one founder. If we are worried about aphid success rate and have fewer replicates, Dave suggested that we have two founders and just record whether one or both birth their aphid babies within the first one or two days of the experiment. Dear readers: Comments or suggestions about aphid founders are encouraged!

One problem: whatever sort of aphid we use, we need to introduce gravid ones to our plants or there will be no population growth whatsoever and our experiment will fail epically. Thus it is now necessary for Lauren and I to be able to identify gravid aphids. Hmm. Apparently this is possible, and this is something we are going to have to figure out before our actual experiment can start. Again: comments or suggestion are encouraged!

I think that covers most of the updates in the glorious and exciting world of me, Lauren, and aphids.

Over and out!
-Hillary

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Hi I'm Lauren Hobbs. I am from a town in Wisconsin almost as small as K-town (aka Williams Bay). I attend UVA and am a psych major. Hence I am learning a lot already!! Fortunately, I found a friend here to work with!

Hi! My name is Hillary Lyons and I am from Olympia, WA. I am a biology major from Carleton College. I really like muskoxen.

proposal.pdf

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As per a request from Daniel, here is a presentation I gave to Team Echinacea way back at the beginning of the summer. Enjoy reliving the magic!

Aphids and ants.ppt

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So, I know I have been missing from the flog lately, but that is only because I was saving up all my flog posts to make one huge, wonderful one! But this is not that post. First of all,
AphidSearch09FinalVersion.mdb
Here is the aphid search data for the past 6 weeks. Each plant has a unique RecordID that identifies it though all three tables. The UnitID field, while it might seem repetitive, is just from the format used on the Hjelm house computer. We have found 263 plants so far, but about 20 of them were can't finds in following weeks.

This still lacks the transect searches that we will do next week, at which time I shal post an updated version. Note that even though this says Final version, this is just where I save all the final versions of my tables, as opposed to the working versions I use to sort out the tables.

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Hello all!

This is Daniel with another update on what team Echinacea has been up to in the past week. Allegra, Stuart and I have become what I like to call the "Staffanson Crew", and we are responsible for doing phenology at Staffanson every other day. Today we got the time down to about 2 hours and 20 minutes, from 3.5 hours originally. The process was made a lot more efficient by splitting up sections and giving everyone a separate checklist. Of course, the temperature was almost 40 below, so that was slightly unpleasant. Add the wind and the fact that I was only wearing 2 thin layers, and you have a recipe for hypothermia. However, I persevered, thinking of my avocado and sausage sandwiches waiting for me at the Hjelm house.

The pollinator project has been going along well, with Kate, Amanda and Mimi hard at working sorting out the oodles of data they have obtained. Greg and Kate are based in what I like to call the "Basement of Oppression", working on making slides and taking pollen photos. Amanda is pinning bees and creating agar slides with the different pollen loads, then photographing them. Finally, Mimi is working on sorting out all the different types of flowering plants found at each sites. Meanwhile, who knows what Amy and Caroline are up to? Reviewing papers and entering data most likely, tasks far beyond the comprehension of we undergrads.

In my case, I have been searching for the different plants in the common garden that we identified as having spittle. I spent all afternoon in the common garden yesterday, and it was a ton of fun, especially since I saw so many interesting things. The most interesting thing of all though, was watching a bunch of ants pick up and move an aphid that was sitting on a leaf. The aphid may have been dead or alive (alive would be so cool!), but since I was silly enough to forget my camera, I guess I'll never know.

Most of the plants I looked at have aphids on them, but I will need to wait until I finish looking at them all before I draw any conclusions. Meanwhile, our transect searches are done until next week. However, I have found aphids on many of the plants I saw during our Staffanson searches, so I remain hopeful!

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Here is an outline of the form needed for doing the aphid searches:

Rosette Count

Leaf Count

Length of Longest leaf - cm

Ant Presence - Yes/No

Size of Aphid Infestation (Required Field) - Categories 0, 1, 2-10, 11-80, >80

Count of Leaves with Aphids

Spittlebug Presence - Yes/No

Distance from Plant to Spittlebug - 0 if on the Echinacea Plant itself

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So, in an attempt to fit as many sampling needs as possible, here are the sites that we will be sampling for aphids, juvenile plants, and some tissue samples, along with the sampling strategies:
Large and Less Isolated
Staffanson(SPP)
Landfill(LF)
KJ's
Medium
Nessman (Ness)
East Riley (Eri)
Steven's Approach (Stevens)
Northwest of Landfill (NWLF)
Small
Randt
East of Town Hall (ETH)

We will use a couple different sampling strategies for the different remnants in order to try and randomize them as much as possible. These should accomodate Daniel's, Amy's and a portion of Jennifer's project. Note: All belt transects are 1/2 m unless otherwise noted.

Staffanson - Select 3 random locations in both the burned and unburned plots using randomly selected ULM coordinates, and find them using the Trimble GPS. Then, choose a random compass direction and run the belt transect roughly 10 m in that direction.

Landfill - Choose 3 random locations on the East Hill (Trimble again), choose a random direction, and do a 3-5 m belt transect in that direction. If more plants are needed, go a little further

KJ's - Choose 3 random locations, choose a random direction, and do a 3-5 m belt transect. Go further if needed.

Nessman - Since this is a roadside remnant, choose 5 random points along the road edge, and extend the belt perpendicular from the road to the cornfield.

East Riley - choose 5 random points along the road edge, and extend the belt perpendicular from the road to the edge of the remnant

Steven's Approach - Choose a bunch of random points along the road, and inspect to see if there are plants present. If not, go to the next point.

Northwest of Landfill - choose 5 random points along the road edge, and extend the belt perpendicular from the road to the edge of the remnant.

Randt - Choose a bunch of random points along the road, and inspect to see if there are plants present. If not, go to the next point.

East of Town Hall - Select random points used for seedling search, and look for plants there.

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This file lists places to look for spittlebug spittle masses in the CG. At the top there are rows in the 99 garden and the 99S garden sorted randomly. Then all bigbatch rows (noted with end positions) are listed in a random order.

Enjoy your search!

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So, *drum roll please*
Here are the possible candidates for the remnants that I will be looking at this summer.
In no particular order, I will pick 7 out of:

KJs
NW of Landfill
Landfill
Krusemark
East of Town Hall
Aanenson
Randt
Yellow Orchard Hill
Nessman

Depending on what Amy needs for her seedling searches, I can adjust accordingly, but these sites should give a good cross-section of isolated prairie remnants and well populated ones. Tomorrow, we will spend another hour searching for spittlebugs in the common garden, and hopefully enough will be found for a sufficient sample size. Phenology has also started in the common garden, and we have 4 plants that are flowering so far, with hopefully more by tomorrow.

We went out to the Glacial Lakes reserve today for a hike, and it was incredibly beautiful. We took lunch and hiked all afternoon, seeing some flowering Echinacea, noticing a bumblebee on one of the flowering Echinacea, and stopping every 5 minutes to look at a new plant. We even did a few seedling searches! (Stuart has trained us well....)

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So, here is my revised project plan. I spent about 2 hours with Stuart today going over the procedure, and I think the randomization aspect and sampling aspect has been redesigned a bit better.
DanRathProposal.doc
Please let me know what you think. A bit more revision is to come, but this gives the basic idea.

Today was a beautiful day on the prairie. Got to try out my new bike this morning, and rode to the farm in a half hour. That last hill is a killer though. This afternoon, I rode back along Unity Drive, and noticed some Brome grass that had its anthers sticking out. Mistook it for a new type of plant at first. Nice warm weather with a nice breeze, so wonderful bike riding on those gravel back roads. Pictures will come eventually!

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So, here is my proposal for looking at aphid proportion and density in the different prairie remnants this summer, as well as the presence of spittlebugs. Please criticize and let me know what you think.

DanRathProposal.doc

For the preliminary observations done to get an idea of the number of plants with aphids, I spent yesterday morning scanning the common garden for Aphids. I looked at rows 2, 3, 14, and 40, and wen through them up to the 20 meter mark. I found 3 plants with aphids and 5 with spittlebugs. For the younger plants, I scanned rows 51, 54, 55, and 56, and found 5 plants with spittlebugs and 3 with aphids. Given that I missed some, I would say that of the 270 plants looked at, roughly 2% had aphids.

Yesterday afternoon was also spent pressing plants, where I learned some of the finer points, such as ensuring that the flowers and leaves were well separated, how to fold some plants over, and to ensure that some leaves were turned over so that both sides of a leaf were captured. It is also very important to label clearly, and BEFORE you put the plant in the paper.

The little miss Runestone parade is today, and it is very likely that pictures of this event will be referenced or posted in later posts. (Depending on the varying levels of cuteness).

Also, here is the really cool paper on Spittlebugs, aphids and ants that I found: http://psyche.entclub.org/pdf/97/97-043.pdf

Daniel R.

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