Joanne in S.A. is having problems with budworms attacking her roses. Budworms are caterpillars of the Helicoverpa moth family (previously called Heliothis moths). These destructive pests also attack stressed plants of sweet corn, tomatoes, a range of other fruits and vegetable plants and ornamentals.
The moths lay their eggs at night on young foliage close to fruits or flower buds and the young caterpillars feed on the foliage first before moving into buds or developing fruits. After several weeks of feeding, the caterpillars burrow into the topsoil beneath the plant and pupate until rain that produces a burst of new plant growth will signal an opportune time for adult moths to emerge from pupa cases and lay eggs. If you netted plants after the first moth attack, they won’t be protected from further attacks because the pupating moths will be inside the netting.
The first thing to do is remove all damaged buds, fruits/vegetables and caterpillar-infested young foliage and give them to the chooks or dispose of them in a sealed plastic bag – not in the compost heap. Then spray young foliage near buds and fruit with a registered organic treatment that is effective against this moth larvae. Nature’s Way Caterpillar Killer and Naturalyte Insect Killer are a couple of examples. Check daily for individual eggs laid on young foliage and respray when necessary, or after rain. The caterpillars have to be controlled before they enter buds or fruit where the sprays are not effective.
Although rain stimulates egg laying, we have found that this moth only lays eggs on plants that have had a period of water stress. Plants can only absorb the elements they need for pest-resistance from damp soil, and water stress provides the conditions that make them susceptible to attack from this and other pests. Where water is in short supply, apply a 5 cm layer of mulch around your plants and use an upturned 2 litre plastic container with the base removed and the neck embedded into the top soil to apply water efficiently, directly to the root area of plants (see photo). After rain, give plants a drink of organic seaweed extract tea to assist in building disease-resistance.
An environmentally-friendly way of getting rid of stink bugs is to use a stick to knock them into a container with some methylated spirits in the bottom of it, so that you don’t have to come in direct contact with these smelly bugs that change colour from green to orange to brown-black as they grow.
However, a reader e-mailed me this week about his problem with lots of stink bugs on his orange tree that is too tall to use this method, and he wanted to know if he could spray the tree with metho, instead.
Spraying the bugs with methylated spirits would only further damage the tree. If you also have a tree affected by bronze orange bugs (stink bugs), these bugs are a sign that a tree is very under-nourished. It is probably extremely water-stressed, as plants can’t absorb nutrients from soil if it is not damp enough for the minerals to become water-soluble. Give the soil around the affected tree a thorough watering, then give it an application of complete organic fertiliser and then water in some organic seaweed tea. You haven’t said which climate area you live in. If you live in an area where water shortages are common, keep the tree pruned to a size where it can remain healthy on the amount of water that you and nature can provide.
Bronze orange bugs or stink bugs and harlequin bugs are sap sucking pests that can do a lot of damage to stressed citrus trees. Spined citrus bugs suck sap from fruit. Before dealing with these bugs, you need to don old clothes, sturdy shoes, gloves and goggles or sunglasses as bronze orange bugs eject a corrosive fluid with a vile smell when they are threatened.
Young bugs tend to cluster under the lower leaves of the trees and are easy to get at, but if trees are too large for knocking them into a tin, spread some large sheets of plastic under the tree, then use a broom stick or long pole to give the foliage a good shake and, when they drop to the ground, either squash them, or gather up the plastic and slide them into a large container with a suitable pest treatment in the bottom.
Organic-registered products such as Natrasoap (not ordinary soaps or detergents) or Eco-oil will kill these pests but they should not be used on heat-stressed or water stressed plants, or in high temperatures. However, either of these products can be used to spray stink bugs when they shelter around the base of the tree on hot days. Harlequin bugs like to shelter in weeds, and they can be sprayed where they are hiding. Get rid of weeds, particularly along fence lines to prevent re-infestation.
However, the best way to avoid these horrible pests is to take good care of your citrus trees.
I am concerned to hear that CCA treated timber has been used to construct garden beds and other structures in some school gardens, so it might be a good time to remind readers that the uses of these timbers have been restricted.
Since the end of March 2006, timber treated with copper, chromium and arsenic as a preservative (CCA timber) is not permitted to be used for garden furniture, picnic tables, exterior seating, children’s play equipment, patio and domestic decking, or handrails. Problems with CCA treated timber
The restrictions on use were implemented by the Australian Pesticides and Veterinary Medicines Authority (APVMA) because they were “not satisfied that the continuing use of CCA for timber used in structures with which the public (and particularly children) are likely to come into frequent and intimate contact is safe“.
Common sense would dictate that the APVMA restrictions would also apply to garden beds (as they do to sand pits) because this timber can leach arsenic (a known carcinogen) into compost and soil for up to 20 years, and some species of food crops can absorb high levels of arsenic.
As young children have a tendency to put their fingers in their mouths, and tend to be less careful about washing their hands, they can ingest significant amounts of leached arsenic, a known carcinogen, from CCA treated timber. Children are, of course, more vulnerable to all pesticides because their organs are still developing and young children eat more food per kilogram of body weight than adults do.
The APVMA’s decision follows the phase-out for domestic uses of CCA treated timber in the US, EU, Canada, Indonesia and Vietnam, and restrictions to its use in Japan.
The regulations allow the use of CCA treated timber for ‘structural timbers’ and the timber industry has included retaining walls in that description. However, the APVMA Review (page 11) clearly states, structural timbers “where frequent contact is unlikely, and the level of exposure and risk, is low“. Once installed ……..
Research by the US EPA (in 2005) found that penetrating sealants can reduce, but not eliminate, arsenic migrating from the treated wood. The data show sealants that can penetrate wood surfaces are preferable to products such as paint, because paints and other film-formers can chip or flake, requiring scraping or sanding for removal, which can increase exposure to arsenic.
More recent US research has found that arsenic levels on CCA-treated wood remained high for 20 years, and that timber had to be re-coated every 6 months, making the maintenance of this timber to reduce students’ exposure a tedious and expensive process. The only safe solution is to replace the CCA treated timber with one of the safer alternatives that are now available. APVMA Review
Following my post on organophosphates and ADHD, one of my blog readers asked for more information about derris dust (rotenone) that has been popular with organic gardeners for pest control as rotenone is an organic pesticide made from the roots of a tropical plant. It also has a long history as a piscicide (fish killer).
Rotenone works by shutting down energy production in cells, which makes it a neurotoxin. Research linked it with Parkinson’s Disease, but this was largely discounted as the rats in the research had rotenone injected directly into their brains, which is not a very fair trial.
In 2007, the USEPA published a Re-registration Eligibility Decision (RED) assessing only the risks of contact from its use as a piscicide (i.e. swimming in or drinking treated water). The RED stated that small children and foetuses were more susceptible to the effects of rotenone. www.environmentalhealthnews.org/ehs/blog/health-ecosystem-effects-of-rotenone-ignored
According to Environmental Health News, researchers have found that rotenone selectively destroys dopamine-producing cells in petri dishes. (The full document on this research must be purchased).
In 2010, another study was published about research in mice that showed a progression of Parkinson’s-like symptoms after mice were fed low doses of rotenone over a period of time. The research found that concentrations in the central nervous system were below detectable limits, yet still induced Parkinson’s Disease pathology.
Australia’s APVMA has reviewed rotenone and decided that it can still be used as a pesticide. However, both Canada and the United States are phasing out the use of rotenone for everything except its use as a fish poison. In Canada, for example, rotenone could not be sold for livestock, gardening, or domestic pet use after the end of 2008, and existing stocks can’t be used after the end of 2012.
I certainly don’t recommend the use of Derris dust, but gardeners must make their own evaluations of this pesticide.
Earlier this week, ‘Today’ program on Channel 9 aired a segment about new research showing a link between organophosphate pesticides and ADHD. The research involved 1,139 children between 8 and 15 years and found high levels of organophosphate metabolites in urine of children with ADHD. This link is not surprising as organophosphates (and carbamates) are neurotoxins. These pesticides work by affecting the central nervous system, and organophosphates were developed for chemical warfare before being used as pesticides.
Both organophosphate and carbamate pesticides block the action of the enzyme acetyl cholinesterase, which regulates the transmission of nerve messages. Well-established research has shown that chronic exposure to organophosphates induces neurological dysfunction. Children are more susceptible to all toxins, including neurotoxins.
Separate research has linked pesticide exposure with Alzheimer’s disease and Parkinson’s disease. Included in the suspects is the very popular Derris dust, which has also been found to be a neurotoxin.
‘Today’ presenters advised that all fruits and vegetables should be carefully washed before eating. Good advice to be sure, but advice that misses the point that some organophosphate pesticides commonly used on food plants are systemic. Systemic pesticides enter the sap system in plants, are distributed to all parts of the plant, and can’t be washed from our food. As a lot of our food is now imported from countries with differing standards for pesticide regulation, we have no way of knowing whether or not our food contains systemic organophosphates. AQIS carries out testing on only a tiny percentage of imported foods.
Write to your federal Member of Parliament requesting a ban on the use of systemic organophosphate pesticides in local produce, and improved inspections and standards for imported foods. Remind your Member of the cost to the community in treating the problems caused by these pesticides. Where possible, buy organic produce for your children, and grow as much as you can using organic methods. It will not only be healthier – you will notice it tastes better, too.