Roots 'n' Shoots: August 2014

Why is RnS Moving to




- The Shroom - (AKA Whisker Flowers)

Saturday, 30 August 2014

Spiders: Biological Control - Garden Critter of the Month

Spiders at a glance

Value to Gardener:
5/5 - Pest Controller!
Danger to Humans:
4/5 – Some are very poisonous
5/5 – They’ll arrive in your garden

Quick Intro

Most people shriek at the sight of a spider and try their very best to stomp it out of existence. I believe that spiders have the worst reputation as terrible poisonous scary things (apparently 50% of  women display symptoms of Arachnophobia!), but if you just let them be, they are super garden helpers who are the fundamental front-line in biological control and the battle against pests!   

Kunstformen der Natur
Kurt Stubers Online Library

Science Stuff

True spiders fall within the Araneae order amongst the other spider/scorpion look-alikes in the class Arachnida. Spiders are distinguished from the other orders by virtue of several characteristics, such as:

ü    Spinnerets: Modified appendages at the rear of the abdomen that manipulate silk produced from the silk glands.

ü    Enlarged pedipalps in males: These look like little “boxing gloves” and have evolved to transfer sperm to the female during courtship.

Spider Morphology

Spider anatomy

Several families of spiders exist within Araneae. In general, the garden biological control agents are of the smaller type and likely not deadly poisonous, except Widows and Sac Spiders are very poisonous, so just steer clear of these.

Black widow and Sac spiders


Spiders occupy several niches within the environment and are found at various layers (for example, canopy habitats; where they wait in ambush or they are found running between the grasses and actively hunting prey).

The most common method of prey capture is through trapping, such as webs. Spider webs can be occupied singly (usually a large female, sometimes accompanied by a smaller male, such as orb web and tent spiders). Whereas others construct huge web structures that span entire forest clearings where multiple social spiders tend to the web and prey is shared, for example as with social community spiders. Ground dwelling spiders may burrow and ambush prey, such as baboon spiders or tarantulas, whilst wolf spiders run and actively hunt for prey.

For every ecological level in the garden, from the ground, the lower plants, shrubs and trees, there are spiders that occupy each of those levels. They also come in a variety of sizes, where small jumping spiders or spiderlings hunt small pests (such as aphids or whiteflies) and larger species can deal with larger prey, such as leaf hoppers and caterpillars. Therefore, spiders provide a full spectrum biological control on flying and crawling pests.

Crab spiders, green (top left), white (bottom left) and pink (right). Ambush species
Thomisus species
P.S: Small flies on the bee are known as jackal flies (Milichiidae), they eat any mess from the spider

Hairy Field spider, web spinning species
Neoscona species


Spiders are considered to be predators, but as with most of nature’s creations there are exceptions. Some species’ spiderlings (these are small spider nymphs, during the second stage after hatching) feed nocturnally on nectar. Others may feed on dead insects (scavengers) and pollen.

Predatory spiders are considered generalists and unfortunately don’t differentiate between pest and beneficial insects. In general I find that spiders catch beneficials (bees or ladybugs) far less than pest species, such as aphids, flies, leaf hoppers and stink bugs.

Small jumping spiders eating an aphid (left), fly (top left) and one giving me the evil eye (bottom right).
Ambush species
Salticidae spp.

Large jumping spider eating a leaf hopper
Salticidae species
Another Spider Tip

Providing places for spiders and maintaining them are very easy. You would want some strong sturdy plants, such as basil or dense clumping ones, such as Sterlitzea or Bougainvillea that provide plenty web space. Additionally, do not disturb these areas too often as this leads to a decrease in the overall spider population.

My main spider colonies consist of semi-social garbage line and hedgehog spiders that live in the Sterlitzea where they construct several layers of webbing. I don’t disturb them too often which means I have a permanent pest trap in my vegetable garden.

Garbage line spider
Cyrtophora species

Hedgehog spider
Cyrtophora species

Something Interesting: Spider venom biopesticide!

Most spider venoms are deadly to insects but not harmful to vertebrates. This initiated research into spider venom based pesticides as bee-safe alternatives to chemical insecticides (specifically neonicotinoids). 

Lynx spider, active hunter
Oxyopes heterophthalmus

A particular protein found in the venom of the Australian Funnel Web Spider, Hadronyche versuta, targets the calcium-channel in the insect central nervous systems, causing paralysis. This protein is combined with another ‘carrier’ protein (the result is known as a fusion protein) to stabilise it and allows the toxin to be used as an oral pesticide. This potential biopesticide can be used against Lepidoptera (butterflies and moths), Coleoptera (beetles) and Diptera (flies). Researchers suggest further evaluation of this biopesticide on other beneficial Hymenoptera, such as bumblebees and parasitic wasps.

The development of biopesticides in conjunction with pollinator toxicity tests might provide more environmentally friendly alternatives to the conventional pesticide - and a more sustainable approach to farming!

For the original scientific paper (free and downloadable from): 

False house button spider, female, egg sac and male
Theridion species



Monday, 18 August 2014

Roots 'n' Shoots Birthday (Blogiversary) Post #3




Tiny time capsules
Rose moss seeds


(2) research, research and more research,
(4) *wait for screen loading*
(5) write the post,
(8) upload pictures,
(9) *more loading* - *sigh*
(10) add any attributions or references,
(11) double check links and




Honey bee on Garden Heliotrope




My attempt at a Garfield inspired bird deterrent painted rock!




RSS Feed: Feed Reader at

Twitter Account:
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Wildlife spottings in our area: My Project Noah account @





World Kitchen Garden Day

TTFN - Ta-Ta For Now!

The Shroom

Posts mentioned in the article:

Starting a Productive and Economical Vegetable Garden: vegetables worth growing


Tuesday, 5 August 2014

Earthquake hits Central South Africa!

Libanon Mine of Sibanye
near Westonaria, South Africa
South East of Johannesburg in the Earthquake zone

At 12h44: Wow! We just had a tremor run though Roodepoort (near Johannesburg, Gauteng) at approximately 12h25! Seems that this isn't the first time that a tremors or earthquakes have struck. There have been a few in the past as well, this one was felt by some of my friends in Pretoria (South) as well and likely originated from an old mine shaft that collapsed, (maybe the Brixton one again, not sure!).

Updates to follow!

At 12h55, alright from the people coming in on this post (from my blog stats), it seems people felt this in:
Cape Town
East London

At 13h00: The reports are in!

Time of occurrence 12h22

Earthquake of 5.3 magnitude! (Amended to 5.5 by experts at a depth of 10 km)

Centered in Orkney, 120 km Southwest of Johannesburg! An area with many gold mines. At around 13h15 South African gold miners with head offices in Johannesburg and Sandton advised that they had felt the earthquake at their head offices but have so far received no reports of damage from their mines. 

Earthquakes and deep level mining does not bode well and I hope that no mine workers will be injured.

Seismometers measure earthquakes according to the Richter magnitude scale, which quantifies the amount of energy released by an earthquake - more specifically total moment energy.

Measuring at 5.3; today’s earthquake can be described as ‘Moderate’. It can cause damage to building with poor construction and everybody will feel its tremors. On a global scale, approximately 500-1500 of these earthquakes occur per year. Only earthquakes that reach above 7 cause great damage to buildings and are classified as Major (around 7) and Great (above 8). Earthquakes of magnitude 8 release an equatable amount of energy to 6 million tons of TNT!

Earthquake hits central South Africa
Google maps platform ©
Red marker: Earthquake origin at Orkney
Blue maker: Roodepoort, Gauteng


Reuters Africa
3) International: USA Today

At 14h45: Can we expect aftershocks from this Earthquake event?


After some research the short answer is: YES.

Magnitude 5 (M5) earthquakes can generate aftershocks minutes after the initial event that can last for days. These will be with in a 10 kilometre radius from the epicentre These follow a precise sequence and there may be 10 aftershocks of magnitude 4; 100 of magnitude 3; 1000 of magnitude 2 and so on, which by then would no longer be felt by people. Also most of the aftershocks occur hours after the initial event an soon dissipate, likely ceasing on the second day.

Aftershocks were felt mostly in Gauteng:
Reference: Aftershock Studies

At 16h00: Tectonic events and the Witwatersrand Basin

There is a large and complex formation of rocks around the Witwatersrand area. It has one of the largest gold reserves in the world as well as numerous other rock series such as quartzites and ironstones, collectively known as the Witwatersrand Supergroup.

In this area is the largest concentration of South African gold mines including some of the deepest, most of which are 120 kilometers from Orkney.

Mponeng: Near Carletonville and is 2.4-3.9 kilometers deep. It is the deepest gold mine in the world!

TauTona: Also near Carletonville, 1.85-3.45 kilometers deep. It is the second deepest gold mine in the world!

The geological area around the Witwatersrand Basin is prone to tectonic events due to underground movements and fault lines. Reference: The Witwatersrand Basin South Africa: Geological framework and mineralisation. 1995. Robb L. J. and Meyrs F. M. One Geogolical Reviews: 10. 67-94.

The Witwatersrand Basin had generated a tectonic earthquake and several mines in the vicinity could have been effected as well. Such as the Great Noligwa (1.5-2.6 km deep), Kopanang (2.1 km deep) and Moab Knotsong (2.6-6.3 km deep). See diagram for mines near Orkney below:

Witwatersrand Basin Mine Locations
Source: Mineral Resource and Ore Reserve Report 2013,
AngloGold Ashanti

At 18h30: Are more earthquakes imminent? Should South Africa expect another earthquake in the future?

Yes, many factors indicate that this area might generate more earthquakes in the future due to tectonic plate movements. Therefore it becomes a question of WHEN and not IF.

The Witwatersrand Basin is likely susceptible to tectonic activities from the African Plate fault line, which extends through middle (more to the Eastern side) of South Africa and in the earthquake zone. The plate on the Eastern side (Somali African Plate) is moving away from the Western (Nubian African Plate) and will likely generate more earthquakes in the future. Please see the following map and blog post: World Maps of Fault Lines and East Africa: The Next Continent.

At 19h00: Earthquake awareness for Africa and What to do when a earthquake strikes!

Scientists have been calling for greater awareness of the occurrence of earthquakes in Africa due to the shifting plates. The Millerton fault in the Cape has the potential to generate magnitude 6 earthquake. The key to earthquake management is to be prepared and stay safe rather than earthquake prediction.

The key thing is when you are indoors and an earthquake strikes is to avoid being thrown or hit with falling objects. Therefore climbing under and holding onto your desk is the safest place indoors.

If you are outside then move away from buildings or walls and stay in the open. When an earthquake occurs while driving, move off the road and stop the car avoiding overpasses or other large objects that may fall over.

After the earthquake, check for fires and check that the phones are working. Be aware of stored objects in cupboards as they might fall out.

For more information on how to prepare for, what to do during and after an earthquake see the following websites:

How to Protect Yourself During an Earthquake
Be Prepared Before, During and After an Earthquake

Other references:

Cape Town Earthquakes: Review of the Historical Record by C. J. H. Hartnady
Scientists Call for Earthquake Awareness in Africa

On 6 August 2014 at 13h00: News about the chances of another earthquake have been aired.

Again it is a matter of when and not if. We can expect one of the same magnitude in the future due to the mining activities in the Orkney region that disrupts the geological statues of the Witwatersrand Basin and the African plate fault lines. ... Seems like my initial thought that mining was involved in some way was correct...

See News bulletins (the first with a video from a Geosciences expert):

Another earthquake of equal magnitude expected: expert
Quake triggered by mine activity - expert


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Absolutely Gorgeous Beautique