Green Grass Without Synthetics

There are benefits to having grass in parks and residential properties. When taken care of, grass becomes a natural carpet on which one can easily rest, play or walk. But to keep Poa pratensis green and thus in a juvenile state requires an investment of energy, an amount that is exaggerated by our questionable habits.

The typical high maintenance option involves buying synthetic fertilizer for spring and autumn applications, herbicide for weeds and pesticides for grubs. Some hire a company to drive around the neighbourhood to periodically spray lawns with the necessary concoction. To avoid the nuisance of a long electrical wire, people buy  gas-powered mowers.  And to prevent leaves and tree seeds from accumulating on lawn, blowers come to the rescue.

Even if people with such habits are aware that making fertilizer is an expensive  process partly because nitrogen does not spontaneously react with molecular hydrogen; even if they know that some fertilizer-pellets inevitably get sprayed onto sidewalks where they damage concrete, induce diarrhea in dogs and end up in storm drains and eventually into waterways and contribute to eutrophication; even if they suspect that the use of pesticides has ecological consequences;  even if they are aware of  the carbon footprint of synthetics and mowers and of the noise pollution of blowers, there is a possibility that they persist with their habits because they believe there is no alternative.

But when there is a will to change, there are always other options. One reason people turn to mass-maintenance techniques is that they plant more grass they can handle. City parks or residents can instead plant more trees, shrubs and cultivate gardens, which is what we did with 2/3 of the lawn we originally had in our backyard. I never spray any of our fruit trees or apply any pesticides to our garden. Instead of synthetic fertilizer, we rely on  a combination of household compost and composted chicken manure.  Grass cannot be eaten, but from July to October we have not needed to buy any tomatoes, garlic, parsley, basil, thyme or Swiss chard. We still have frozen cherries from our tree and we’ve also enjoyed arugula, fresh beans, onions and Mexican peppers, most of which were grown from seed.

P1150783.JPGA city bylaw prevents us from cultivating the front yard, but I manage to sneak in some oregano and bird’s-foot trefoil. They require less water and nitrogen than Kentucky bluegrass and displace  weeds. Since our city does not use pesticides on the grass between our sidewalk and road, dandelions, crabgrass and plantains find their way into our property. But I just pull them out with a hand tool. As an alternative to synthetic fertilizer, mulch from the electric mower is left on the lawn so that essential elements like nitrogen, phosphorus and potassium can be recycled. To supplement the lawn with more natural fertilizer, we let the dog pee on it and then immediately add collected rainwater to prevent “burning”. Due to their carnivorous diets, dogs’ urea is highly concentrated so it easily creates a hypertonic solution that needs to be diluted. In the spring the melting ice and snow takes care of that. Spots that don’t receive their share of dog pee get coffee grounds, which also keep the lawn green.

Abating the effects global warming involves more than reducing the use of fossil fuels for transportation and electricity-generation. They only account for a combined 45% of greenhouse gases(see pie chart below). Just about everything else ranging from reproduction to growing grass and food also impacts climate change. To solve the problem, regardless of the field of human activity, green or technical, we have to conserve and act more benignly towards ourselves and our surroundings.

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AFOLU is an acronym for agriculture, forestry(deforestation) and other land uses. Its large contribution to greenhouse gases is often ignored in media reports about climate change. Source: www.ipcc.ch/report/ar5/wg3/
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Queen Bee Chemistry

It is so easy to jump to conclusions when observing and studying honeybees. To the uninitiated, the female workers seem to be the key to the hive. After all, they do so much. They start off early in their lives cleaning the nest. A few days later they are feeding larvae, then secreting wax to build the honeycomb. At about the age of 20 days, they act as guards to the entrance of the nest, and when their glands degenerate, they’re off collecting pollen and nectar for the rest of their lives. After a successful trip, they perform elaborate symbolic dances, revealing both the angular and scalar components of their displacement from flowers to hive. In contrast, the males and the queen bee don’t do any of the above.

But the female workers, as industrious as they may be, do not reproduce and do not exert the strongest influence in the hive. The failure of a single and other type of individual is consistently listed as a cause of honeybee colony mortality.  That individual is the queen bee. She is born in a cell built larger than the others to accommodate her bigger size. But what makes her develop into a queen? After observing that the queen bee larva and adult queen is only fed a so-called royal jelly, a white mixture of protein and sugar secreted from the heads of worker bees, it was long assumed that the mixture held the secret. But a few years ago it was revealed that the key was not necessarily contained in the royal jelly but in what the queen bee was not fed: pollen and nectar. The latter food- source for other larvae contains flavonoids, some of which include inhibitors. Investigators reared larvae in the lab on a royal jelly diet adulterated with para coumaric acid, and by the time they developed into adults, ovary development had been stunted.

queencourt
A queen bee courted by other females. Notice her  larger size and the yellow marker added by a biologist. http://articles.extension.org/pages/73133/honey-bee-queens:-evaluating-the-most-important-colony-member

When not exposed to such gene-silencers, a queen bee will normally emerge from her larval stage five days sooner than other bees. After killing competing virgin queens, she diversifies genetic input by mating with 7 to 17 drones, who die soon afterwards. With the ability to store about seven million sperm, the queen will then be fed and groomed by workers while she lays eggs for the rest of her life. In what surely is a matriarch’s fantasy, the older a queen bee gets, the more prolific she becomes in laying eggs, becoming even more attractive to her servants. But how does this happen?

JBFree_source-Pheromones
The various effects on bee behavior controlled by a complex of a chemical signals from the queen bee. Source: JB Free

It has been known for decades that a pheromone (chemical messenger) is released from the queen bee’s mandibular gland in her lower mouth.  In subsequent experiments, however, the compound that had been identified as E-9-oxodec-2-enoic acid, could not on its own exert any retinue behaviour on worker bees. Retinue behaviour is what’s used to described the way workers groom and feed the queen. It’s only part of the influence that the queen bee’s chemical messengers can have on bee behaviour, as revealed in the adjacent illustration. There are a series of effects with immediate impacts (releaser) and those with long term consequences(primer) on the endocrine and reproductive systems of workers.

beehormones
Three of at least 9 compounds released to make sure the queen bee gets groomed and fed by other females.

Eventually, in the late 1980s Canadian researchers from Simon Fraser University revealed that the original compound was really a mixture of two mirror-image molecules known as enantiomers. They also identified three other compounds from the mandibular gland. When a tube containing the 5-compound mixture was placed in a beehive, the workers left the cells that they were building for new queens and started to press their antennae against the glass while licking the synthetic queen. But the mystery wasn’t entirely solved. As the authors of the same study stated in a review paper 16 years later, the 5-compound mixture is ineffective in some strains of honeybees. The response is influenced by variable genetic factors and by at least 4 other compounds, specifically coniferyl alcohol, another alcohol, methyl oleate and linolenic acid. As the queen ages she releases higher concentrations of the compounds to ensure a positive correlation between the attention she receives and the amount of eggs she lays.

When looking beyond the queen and to the general health of bees, including solitary ones, it was assumed that the concentration of pesticides found in bees was too low to harm them. If inspected individually, each pesticide’s level is indeed below the bee’s threshold. But collectively, along with bee diseases and diminishing flower diversity, pesticides have a detrimental impact on a highly beneficial insect. Whether or not bees produce honey and wax for us, they are the sole and essential pollinators of plants such as squash, zucchini, pumpkins, kiwi, watermelon, cantaloupes and Brazil and macadamian nuts. Besides, their mysteries have justifiably inspired more research than any other insect.

Sources:

  • Honey Bee Queens: Evaluating the Most Important Colony Member
    Bee Health October 07, 2015  Philip A. Moore, Michael E. Wilson, John A. Skinner
    Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville
  •  A dietary phytochemical alters caste-associated gene expression in honey bees. Wenfu Mao, Mary A. Schuler, and May R. Berenbaum. 2015. Science Advances 1(7).

  • Pheromone Communication in the Honeybee (Apis mellifera L.) KEITH N. SLESSOR,1 MARK L. WINSTON,2 and YVES LE CONTE3 Journal of Chemical Ecology, Vol. 31, No. 11, November 2005 (#2005) DOI: 10.1007/s10886-005-7623-9
  • New components of the honey bee (Apis mellifera L.)
    queen retinue pheromone. Christopher I. Keeling*†, Keith N. Slessor*, Heather A. Higo‡, and Mark L. Winston‡ Proc Natl Acad Sci U S A. 2003 Apr 15;100(8):4486-91. Epub 2003 Apr 3.

Pesticides in Tea: Strange Brew Indeed

Early in 2014, CBC’s Marketplace decided to investigate pesticide residues in dry tea leaves. After using an accredited lab with a testing method employed by the Canadian Food Inspection Agency (CFIA), here’s what they concluded:

Half of the teas tested contained pesticide residues above the allowable limits in Canada. And eight of the 10 brands tested contained multiple substances, with one brand (Uncle Lee’s Legends of China Green Tea) containing residues of 22 different pesticides.

Following the publication of this kind comes the inevitable comment from the manufacturer, ” Pesticide residues in food are a modern reality but pose no danger at low concentrations”. Health and Welfare Canada then echoed the sentiment. So is this really just journalistic sensationalism?

Far from it. Upon a closer look at the data, here is what I found interesting:

(1)  One of the compounds found in 2/3 of the teas tested was acetamiprid, an insecticide of the neonicotinoid class, which is often used to kill aphids.  A recognised irritant in mammals, it is highly toxic to birds and earthworms and moderately toxic to most aquatic organisms.

ADI – Acceptable Daily Intake (mg kg-1bw day-1) means mg per day per kg of body weight from  University of Hertfortshire’s data base on pesticides. 0.07

0.07 mg kg-1bw day-1 is equivalent to  4.55 mg/day for a 65 kg person.  Superficially, it seems that one would have to drink a liter of Uncle Lee’s Legends of China green tea (1 mg?L= 1 ppm) tea to ingest about a quarter of the “acceptable” limit, but tea is not the only source of acetamiprid.greentea

The same data base I consulted reveals the following concentrations(in ppm) of the same pesticide measured in European fruit:

Citrus: 1.0; Cherries: 0.2; Curcubits with edible peel: 0.3; Pomes, apricots, peaches, tea and hops: 0.1; Plums and cotton seed: 0.02; Cereals, berries, soft fruit, other fruit, vegetables and treenuts: 0.01

(2) As Marketplace reported and contrary to what “Uncle Lee” stated, pesticide residue in tea is not inevitable. Red Rose tea had no detectable pesticide residue because it comes from Kenya, Ceylon, India and Indonesia where presently no pesticides are used in the cultivation of tea and probably not in the surrounding areas either. Bear in mind that pesticides are common in China, Europe and North America. In China:

almost a fifth of China’s soil is contaminated, an official study released by the government has shown. Conducted between 2005-2013, it found that 16.1% of China’s soil and 19.4% of its arable land showed contamination.The report, by the Chinese Environmental Protection Ministry, named cadmium, nickel and arsenic as top pollutants.

They did not release pesticide results but it’s obvious from the tea concentrations that the problem for such compounds is equally severe.

(3) Some teas contained chlorphenapyr, which I found startling. In 2000, the United States Environmental Protection Agency initially denied registration of chlorphenapyr (0.66 ppm in Legends of China green tea) for use on cotton primarily because of concerns that the insecticide was toxic to birds and because effective alternatives were available. However, it was registered by EPA in January, 2001 for use on non-food crops in greenhouses.

In fact the PA stated, “The use on ornamental crops grown in greenhouses is a non-food use so there will be no dietary exposure. Since there are no residential uses of chlorfenapyr, no chronic residential exposure is anticipated.”

Glad they thought so.

The maximum limit for chlorphenapyr in food residue ranges from 0.01 to 0.5 ppm, and the Legends of China green tea surpasses the threshold. Tetley green tea contains 0.14 ppm of the same pesticide.

(4)  Still another insecticide found in Legends of China green tea is imidacloprid, also a neonicotinoid. The concentration found was 0.55 ppm, more than ten times the concentration that kills honeybees.

(For a honey bee, the amount of imidacloprid that must be ingested to kill 50% of the test subjects is an extremely small amount of 0.0037 micrograms.  The mass of an average honeybee is  0.1 g, so we’re talking about an LD 50 of 0.0037 X10-6 g /0.1 g = 0.0037 X10-3  mg/0.1 X 10-3 kg = 0.037 ppm ) (http://www.ipm.iastate.edu/ipm/hortnews/2013/05-10/bees.html)

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