Wednesday, October 27, 2010

DIY (mostly) organic pest control

Effective organic, or mostly organic, pest control can be a very difficult process.  However, with careful "scientific" observation and research anyone should be able to effectively control pests in the garden and around the house with mostly organic methods.  While traditional chemical pesticides are extremely effective they can be a little too effective when they kill beneficial insects.  Chemical pesticides definitely have strong negative health side-effects that if we knew the truth about we probably wouldn't be messing around with as much.  I became a lot more serious about going organic when I learned that scientists often inject mice with pesticides in order to induce cancer or severe allergies (They are injected with higher concentrations than we deal with but it still makes me want to avoid them).  Not that chemical pesticides don't have a place in pest management, I just like to avoid them as much as possible.

So how does a regular person begin doing their own organic pest control?  First you must identify what insects you are dealing with.  In my garden at home I identified three problem insects: cockroaches, crickets, and green caterpillars.  At my work garden I identified cockroaches and crickets.  I observed these insects eating my produce both during the day while tending my garden but also by going out and seeing what was happening at night with a flashlight.  Going out at night was extremely beneficial in that I found almost "Egyptian plague" numbers of crickets around my house.

Three of my preferred semi-organic pest controls.  NiBan-FG uses Orthoboric acid to kill insects when they eat the bait,  diatomaceous earth kills insects as they crawl across it, and Semaspore bait infects crickets and grasshoppers that eat it with a parasitic microbe.  Be sure to wear a face mask when applying diatomaceous earth and to use 'food grade".  Pool filter diatomaceous earth is significantly more dangerous to breath in and should be avoided.  These products, and Bacillus thurgingiensis, can be found online just by typing their name into a search engine.

Second, after identifying the pests I researched online effective organic treatments for these pests.  There are a whole host of organic pest controls and I began testing some.  With each one I used careful observations were made of what effects they had and if they were effective or not.  For example, with chemical pesticides I found slightly decreased growth of my plants but all the insects, including beneficial ones, were dead.  Even the lizards were killed by the pesticides.  Garlic and chili pepper deterrents were also tested.  Both slightly reduced pest problems but not enough.  They were very effective against deterring rabbits though.  Then soap sprays on the plants were tested, also not very effective.  After working though this process of testing and observing I finally came across three products that were effective for my gardens.  Bacillus thuringiensis bacteria killed catapillars effectively, Semaspore greatly reduced crickets, and NiBan-FG killed the roaches and crickets.  Food grade diatomaceous earth was also found effective at killing all kinds of bugs when placed
A "pet" lacewings.
in locations where bugs usually hide.  Corn meal was also extremely effective for controlling ants.  Through more careful observation I learned the most effective times and ways of applying these items.  Over time, beneficial organisms populated my yard, also taking care of some of these and other pests.  I now have an abundance of lacewings (effective aphid control), praying mantis (effective at controlling all kinds of bugs), and lizards (also controlling all kinds of bugs).  Yes, I love all my beneficial organisms!  They are like my little pets.

Finding this combination took me several years and a lot of trial and error but it has been worth it.  Patience and a willingness to try new things is the key.  I am still looking for more effective treatments through careful observation or information I come across.  Also, this pest control costs about $30 per year compared to the hundreds people often spend on chemical pesticides annually.

DIY mostly organic pest control
1. Identify the pests.
2. Research and locate items that control these specific pests.
3. Apply pest control and observe results.
4. Repeat until you come up with a satisfactory solution for your home/garden.
5. Keep observing and be willing to try new things.

The key is careful observation, researching new solutions, and PATIENCE!  Trial and error is the name of the game, you must be willing to accept error!  Each region/area/person has a different set of problems and therefore a different set of solutions.  Any solutions you find specific to your situation can be of great help to others.

Wednesday, October 20, 2010

Foraging the city: Olives

Olives will be ripening now through December in the Sonoran Desert.  So yesterday I took a trip to Encanto Park in downtown Phoenix to see if I could find any olives ready for harvesting.  At the park I found several olive trees ready for harvest.  Olives develop on the tree green and as they ripen their color changes to a reddish-purple color and then finally to black.  They are best to harvest just before they turn black.  Olives grow amazingly well in the desert and are a huge food crop that largely goes unnoticed by the general desert dwelling public.  Very few people actually do anything but be annoyed by and try to get rid of this abundant food source in Phoenix.  So, being that olives are one mans trash, I hope to make that mans trash into a delicious olive treasure.  So I picked three pounds of nice plump reddish-purple olives right off the tree.  The problem and reason why olives are largely considered annoying trash is that if you were to bite into one right off the tree it would be disgusting.  Unprocessed olives contain a bitter compound called oleuropein which makes them unpalatable.  It is so disgusting that if you taste an unprocessed olive once you will never do it again.  (Yes, I speak from experience.)

 One of the olive trees I collected three pounds of olives from in Encanto Park.

In order to make a disgusting olive into a tasty one we must fist brine and ferment it for at least a month.  Both interesting biological processes in themselves.  First the olives were rinsed off and a small cut made on one side of them.  The cut allows for the brine to access the inside of the olive easier and can speed up processing by a few months.  Once all the olives were cleaned and cut, they were placed in a one gallon jar and submerged in an 8% sea salt solution to brine and ferment them.  A weight must be placed on top of the olives so they will not float to the top (We used a one-gallon ziplock bag filled with water to weigh the olives down).  The salt solution will flush the oleuropein out the olives, kill bad bacteria, and allow for lactic acid fermentation to take place.  Lactobacillus sp. bacteria carry out this fermentation and process some of the oleuropein into more tasteful substances.  Once a week for three to four weeks the salt brine must be replaced with fresh brine.  At week three taste an olive, if it don't taste good to you brine it for another week.  At week three or four, or when the olives taste good, drain the olives of the brine and replace it with a flavored vinegar brine.  We will discuss this process and the final vinegar brine more when this batch of olives is done in about a month.
My jar of brining and fermenting olives.  Olives were cleaned, cut on one side, then submerged in an 8% sea salt solution.  To keep the olives submerged they were weighed down with a water filled zip-lock bag.  The opening to the container was covered with plastic wrap to prevent any contamination. 

Monday, October 18, 2010

Plant Breath: Transpiration

Amazingly enough, plants actually breath.  They breath very different in comparison to us but yet they still breath.  Plant 'breathing' takes place through tiny microscopic pores located on the surface of their leaves called stomata.  Through these pores water and oxygen are released but carbon dioxide is absorbed.  This process of breathing is called transpiration and actually pulls and moves water through a plant from the roots all the way to the leaves.   We have developed a very simple way to measure plant transpiration using a tool called a potometer.  Actually, I am sure someone else developed it before we did but we came up with it independently...  but anyway.

At right you can see a picture of our potometer complete with a plant cutting.  The device is made of a 1ml serological pipette and about 12 inches of small diameter rubber tubing.  The smaller the graduated volume marks of the pipette the better.  Ours is actually graduated with major marks at the 10ths (100 microliters) and minor marks at the 100ths (10 microliters).  The pipettes and small diameter rubber tubing (we use 3mm inner diameter but larger can be used) can easily be found for purchase through an internet search and together should cost less than $10.  You could also see if a local school lab would let you have or borrow these materials.  Once you have your pipette and tubing simply join them together.

Next you will need the plant cutting that you are going to test on the potometer.  Before you place the stem in the tubing you must first make a continuous column of water that goes all the way through the tubing and ends somewhere in the pipette.  In order to do this you must submerge your tubing and part of your pipette under water.  Make sure there are no air bubbles in the tubing and pipette.  Then, by keeping the end of the tubing underwater insert the stem of your test plant into it. The stem cutting must be as fresh as possible!  Make sure that only the stem portion of the plant cutting goes underwater.  If the leaf portions of the cutting gets wet the plant will not transpire normally.  When the plant stem is inserted into the tubing make sure it has a tight fit so nothing can escape or enter, and make sure there is no air bubble between the stem and the water.  After all this is done you should have a column of water, with no air bubbles, that touches the stem and ends somewhere in the pipette.  Tape this up somewhere like in the photo above and mark the starting point for the water in the pipette (the starting point will be where the water ends in the pipette).

After your potometer is set-up wait an hour or two and see how far down the water has moved the pipette to determine how much water has been transpired.  The same volume of water that has been removed from the pipette has been absorbed and transpired out of the plant as it 'breathed'.  This basic set-up can be used to make a variety of experiments such as comparing how much a plant transpired in the light vs. dark, different temperatures, comparing different species, and comparing different numbers of leaves.  If you are doing a temperature of light comparison it is best to use the same plant species and maybe the same plant cutting.  If you don't use the same cutting try to use the same number of leaves.  Or if you are comparing different species try to make leaf area as equal as possible for each cutting as much as possible.  A whole variety of tests can be used to demonstrate plant water use with this simple device.

Thursday, October 14, 2010

Gross and easy enzymes: Hydrogen Peroxide and Catalase

Enzyme experiments are often limited to molecular labs with expensive and sophisticated equipment.  There are however several enzymes that can be isolated very easily with minimal equipment and materials.  Catalase is one such enzyme that anyone can access for experimentation.  The process for isolating catalase, though easy, is like so many other cool biological experiments: its kind of gross.  But first, what exactly is an enzyme?  An enzyme is a protein that carries out a chemical reaction that normally would not take place.  Our bodies, along with all other organisms, are loaded with hundreds of different enzymes that control when, where, and what chemical reactions happen.  Specific types of enzymes only carry out one type of chemical reaction but can carry out that reaction hundreds of times over.  Enzymes are essentially what do the 'work' of breaking down or digesting things such as our food and then building food molecules into cells to form our bodies.  The reaction that catalase carries out is converting the potentially harmful hydrogen peroxide molecule into harmless oxygen and water molecules.  This is essentially what happens: 

Catalase enzyme + hydrogen peroxide --> catalase enzyme + water + oxygen
After the catalase breaks down hydrogen peroxide into water and oxygen, catalase is then available to carry out the same reaction again.

 Samples of heart, kidney, and liver blended organs for catalase experiment.  
The sediments at the bottom are tiny chunks that settled out.
In order for us to isolate catalase we must first locate some fresh liver.  We get all of our liver, or any other organ meats, from the local grocery store.  We then take about five to ten grams of liver (slightly smaller than a ping pong-ball) and place it in a blender with 500 ml of distilled or unchlorinated water then blend until homogeneous.  Once you have a homogeneous mixture of liver juice, or any other juice for that matter, place several drops in a test tube.  Next, add several drops of hydrogen peroxide to your liver juice test tube.  If catalase is present in your liver juice, and it should be, foaming should take place.  The foam bubbles are full of oxygen that the catalase is producing by breaking down the hydrogen peroxide.  So the more foam that is produced the more catalase is present.  You can repeat this experiment with kidney juice, or any other type of meat. 
In the picture at right I tested heart, kidney, and liver juice for catalase by mixing them with hydrogen peroxide.  From left to right we see the results for heart (no foaming), kidney (foaming), and liver (slightly more foaming than kidney).  Based on these results we know that heart tissues have no catalase, kidney has catalase, and liver has the most catalase.  So why would heart have no catalase while kidney and liver have a lot of catalase?  Well the liver and kidneys are filtering and cleaning organs so having catalase present in them would aid the cleaning of blood of harmful hydrogen peroxide molecules.  Heart on the other hand is not a cleaning organ so no catalase is present.  Other organs and tissues can also be tested in this way but the liver and kidney are the only ones we have found that contain catalase.  We have also tested plants but have only found spinach to contain catalase for some strange reason.  Why the heck would spinach have catalase?  If anyone can figure that out be sure to let me know. 
Enzymes being large complicated proteins are very sensitive to temperature and pH.  You can do more experiments on catalase by heating or cooling the liver juice to see what effects temperature has on foaming.  Try putting it on ice or boiling it.  Also, try adding a little baking soda mixed with the juice to see how the enzyme works in a basic pH solution or vinegar for a acidic pH solution.  Nearly everything you need to know about basic enzyme function can be accomplished through these simple experiments.  There are a few other enzymes that are also easy to handle in a non-lab environment that I will try to post at future dates. 

Tuesday, October 12, 2010

Basic aquatic biology

The next time you are at a lake or pond you can quickly assess the aquatic life by simply picking up submerged rocks from the bottom.  Depending on the habitat, if you look closely there should be an abundance of life present on and around the rock you pick up.  The slimy layer is not simply 'slime', but a cool and complex biofilm made of algae, diatoms, bacteria, protists, and the slimes they excrete.  There will also likely be several types of aquatic insects present on the rocks (a magnifying glass may be helpful but not necessary).  Caddisflies, mayflies, stoneflies, midges, damselflies, and dragonflies all have immature nymph or larval stages that develop for up to year more underwater.  Some of these species, such as mayflies, may only live above water as flying adults for a few hours before death.  Other larger and better known species such as fish and crayfish may also be present but are often harder to observe.  Picking-up and examining rocks from a body of water is also a trick many fishermen, especially those fly fishing, use to determine what types of things the fish may be eating.  Speaking from experience, knowing a little aquatic biology can make you a much better fisherman!  Bugs, slime, and potentially better fishing skills?  This is biology at its best!

A common Arizona crayfish caught from East Clear Creek.
I tried my hand at examining some of these bugs and slime on a recent trip to East Clear Creek in near the Arizona Mogollon Rim.  To start, I picked up many rocks covered with a thick slimy brown-green biofilm.  Gross to some but cool to the biologist!  On all of these rocks I found a remarkably low number of mayfly nymphs.  Why so few aquatic insects?  On closer inspection of the stream bottom there were dozens of crayfish scurrying.  In Arizona, crayfish are not native and are a nuisance invasive that consumes aquatic insects and plants.  This is bad news for many insect, fish, and amphibian species as they themselves are consumed or their habitat or food source is consumed by the crayfish.  Fortunately, catching crayfish along with examining rocks can be a fun activity that can be used to teach aquatic biology to anyone.  In addition, though I have never done so, crayfish are trapped, eaten, and enjoyed by people throughout the world. 

As with some of the best scientific experiments, there is little to no equipment necessary to examine the things living on or around submerged rocks.  A magnifying glass may be nice for looking at insects though.  A basic aquatic insect field guide is also great if you want to identify species.  If you have a microscope available a sample of the biofilm can be scraped off and stored in a vile to examine later.  But for the more exiting task of capturing crayfish you will need a trap or container of some type.  The container we used on our recent trip was a gallon milk jug with the top quarter cut off and the handle intact.  Holes were also cut in the bottom so water can easily move through the container.  

 In future posts I plan on giving details on how a more thorough investigation of aquatic habitats can be carried out.  I also hope to in the future acquire a trap and maybe have a little crayfish boil of my own. 

Wednesday, October 6, 2010

Cider vinegar experiment

The start of our cider vinegar.

Very few people know how vinegar of any type is made.  Fortunately for us it is a very simple biological process that anyone can do.  If you have a large open mouth glass jar, juice, and a breathable cover you can make all kinds of vinegar types that potentially taste far better than what you buy at the grocery store.  The container must be glass, wood, or stoneware because the acid produced (acetic acid) will dissolve metals.  Also, the juice must be preservative free but can be any type of juice you want.  I have only experimented with apple juice but other juice like grape juice works well also.  Experiment with other types of juice or even by adding flavorings of maple syrup, molasses, or honey.   Warning though, do not over fill your jar, leave at least a few inches of space between the juice and the jar.  If you over fill your jar the juice may overflow and leave a disgusting mess.  In order for your juice to turn into vinegar it must be open to the air on the top so your jar must have a large mouth.  It is extremely important to cover the jar mouth with some type of breathable cover, if you don't you will quickly have a major fruit fly infestation.  And by major I mean lots of flies and lots of potential grossed out people.  We have found pantyhose to work best.  Other covers such as cheese cloth still occasionally allow fruit flies to access and reproduce on the surface of your juice.  But if that happens to you the entire project can be turned into a study of the fruit fly life cycle, something you may or may not have any desire to know about!  But we are making cider here, so once everything is mixed and covered up, place the covered jar in a location where it will not be disturbed and wait.  The entire process will take four or more weeks and the results will surprise you in more ways than one!  It will be extremely stimulating in smell, taste, and sight.  Stop by your container every day and observe what is happening.

The juice will not automatically convert into vinegar though some spontaneous generation.  Atmospheric microorganisms will inhabit the juice through the breathable cover.  First, yeasts and fungi will proliferate in the juice causing fermentation and the production of alcohol.  Then, after fermentation is complete Acetobacter sp. bacteria from the atmosphere will inhabit the now alcoholic juice.  These bacteria will convert the alcohol into acetic acid and thus your vinegar.

We started a batch of apple cider vinegar yesterday and will be posting the surprising results in a little over a month.

Tuesday, October 5, 2010

October in the Arizona desert means one thing...

October in the Arizona Sonoran Desert means its time to start planting the fall/winter garden.  Here we are able to grow things productively 12 months of the year.  October through May its easiest to garden, then June though September gets pretty difficult with our intense sun and heat.  But starting this month I will be planting two different gardens, one in the biology departments garden area and a second at my home.  The Phoenix College biology garden will be approximately 150 sq. ft. and my home garden 100 sq. ft.  In order to make this more of a "scientific" garden observations of plant growth and health will be made on a weekly basis and produce will be quantified.  I want to see how many pounds of food can be produced from these plots of land and then determine the value of this food in dollars.  This is a project that anyone can do, by making it as large or as small as they want or need to.  This can be done at a large scale like we will be doing here or even to the small scale of a single potted plant.  The key to make this work as a scientific activity is to record observations and quantify some aspect of the plants.  We will be keeping a garden journal to record progress, failures, and results.  Later quantified results will be posted on this blog.

This is the Phoenix College Biology Dept. garden area.  
150 sq. ft. of the above plot will be used in this project.

The great thing about any gardening project for the student is that it is extremely flexible.  Projects can be as large or small or simple or complicated as fits the needs of the students.  The amount of scientific knowledge that can be derived from gardening is extremely underrated.  In order for the student to learn the most from their gardening experience the right questions must be asked and the right observations made.  This means planning ahead.  Don't just plant a bunch of seeds and see what happens, plant those seed with a purpose and plan to answer some question.  In my project the question simply is, "how many pounds of food can I grow and what is the value of that food?"  Other questions may involve different fertilizers or soils, comparing hybrid crops to heirloom, or different planting techniques.  Check back in the coming moths to see the results of our gardening experiment.

Monday, October 4, 2010

What the "Practical Biolgy" blog is all about (hopefully)

You do not have to have fancy or expensive equipment to run high quality, meaningful biology experiments.  Most everything you need can be accessed through a computer, a local hardware store, or grocery store.  This is one of the more important truths I have learned in my nearly seven years as a community college lab tech and four years as a biology professor.   Most teachers struggle with a general lack time, resources, and money in order to run successful lab activities.  I have also found that too much money and resources sometimes seriously distracts from a meaningful learning experience.  Most educational experiments are most effective when they are simple and to the point.  Overly complicated experimental equipment and procedures result in students focusing too much on on carrying the experiment out and too little on teaching results and concepts.  Low budgets and lack of resources can actually be an advantage to obtaining real results and practical learning opportunities.  While it is often very difficult for teachers to look beyond complicated equipment and experiments, a little creative thinking that looks beyond the "typical" complicated science can go a long way.  Science should be practical and productive for non-scientists and in order to make it so we need to think simply in our application of complex content.  It is my goal with this blog to apply simple, practical, and inexpensive techniques in order to teach more complicated subject matters.  Many simple lab activities can illustrate more complicated subject matter and actually produce something interesting.  For example, yogurt making illustrated fermentation, microbial communities, food preservation, among other things.  Gardening can be used to demonstrate a whole host of things from soil structure, plant biology, and economics.  Hopefully we can wade through these and many other experiments for teaching purposed in the future of this blog.