Catherine StewartReview: Pests & Diseases of Australian Plants

Pests, Diseases, Ailments and Allies of Australian Plants‘ by David Jones, Rodger Elliot and Sandra Jones is a must-have book for anyone gardening in Australia, whether you grow Australian plants or exotics. Within the first 14 pages, I had sticky-noted six really significant bits of information that I hadn’t known before which will help me grow any plant in my garden more successfully. Considering that I’ve been studying horticulture in one way of another for 23 years, that’s really something.

pestsdiseases-and-ailments-of-australian-plants1PDA&AofAP (which I will use as a short name) is a complete reworking of an earlier 1986 book by Jones and Elliot. I have never owned the 1986 book but I realise now that if I had, it might have saved me considerable grief.

I’d expected that when confronted with a whole book about plant pests and diseases, I’d end up so depressed that I’d never want to go outside again. I couldn’t imagine looking at all those photos of ghastly devouring caterpillars, squishy little scales, deforming galls and disgusting spittlebugs that look like someone has hawked and spat in your favourite wattle tree.

Pests Diseases and Ailments of Australian Plants review copy

My sticky-noted review copy

But, instead, I found that getting the right education to deal with what often feels to a gardener like waves of pestilence crashing down upon every plant you love is actually very empowering. And to know that it can be mostly be done without a host of undesirable pesticides is another empowering thing. I’m not the world’s most organic gardener but nor do I want to prop up my plants with systemic sprays and chemicals that I suspect are not environmentally friendly, even if our local regulatory authority (the APVMA) says they’re OK.

Know your friends
Have you any idea whether the insects you see on your plants are goodies or baddies? To my shame, I must admit that I was belatedly educated when I read carefully through Chapter 3 on beneficial insects and animals. Who knew there were so many? Or how many I’d probably deliberately and inadvertently destroyed over the years, seeing something on a plant and immediately assuming it was a black-hat wearing plant assassin? Lacewings, check, but lacewing eggs? Uh oh, I’d rubbed those funny little things off leaves many times, for some reason thinking that were bad guys. Ladybirds, check, but can you pick the difference between a mealybug (bad guy) and a mealybug ladybird (good guy) which eats scales and mealybugs? Oh dear, now I’m seriously getting the guilts.

Yep, this is a GOOD guy - Mealybug ladybird information in Pests, Diseases, Ailments and Allies of Australian Plants

Yep, this is a GOOD guy – Mealybug ladybird information in Pests, Diseases, Ailments and Allies of Australian Plants

Know your enemies
Far and away the most important part about controlling pests and diseases is to know what’s damaging your plant. Curiously, it’s the bit most of us gloss over, preferring to reach for a spray that’s a grab-bag of control rather than sitting down, examining the plant carefully, diagnosing, identifying, and then working out the best course of remedial action. Or working out that no remedial action is needed.

Photo short cuts

Photo short cuts

PDA&AofAP makes identification easy. Knowing how lazy time poor most of us are, it starts off with seven pages of ‘Photo Short Cuts’ so you can start to get the hang of what kind of things cause what kind of damage. Looking just at leaves, I can now see a clear difference between shredded, skeletonised, strip-eaten, shot-holed, ragged-edged, spotted, and mined leaves. Some are serious and need control, but some are not and should be tolerated.

In the main listings section of the book, there are chapters for each major pest category, eg Pests That Suck Sap, Galls, Leaf-eating Beetles; then each has sub categories, either based on host type or insect type. (you’d be amazed at how many types of cup moth there are).

Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

Each listed pest then has the following subheads – Description, Climatic Regions, Host Plants, Feeding Habits, Notes and Control, so you are in no doubt whether the beastie described is what you’ve got, and what to do about it.

Extensive information in Photos by Tony Wood in Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

Extensive information in Photos by Tony Wood in Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

When we get to Chapter 19: Diseases of Native Plants, there is an important disclaimer about the need to get proper identification of a suspected disease before you do anything. Diagnosing diseases is extremely difficult as you must first discount any possible ‘abiotic’ causes of ill-health, including all the careless or thoughtless things we do in our own gardens, like over and under watering, chucking fertiliser around indiscriminately and cutting roots while we’re digging.

Photos by Tony Wood in Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

Photos by Tony Wood in Cup moths in Pests, Diseases, Ailments and Allies of Australian Plants

Not just a reference book
The photographs in PDA&AofAP are superb – crystal clear and detailed, thanks to the many high calibre contributing photographers, like Tony Wood, Chris French, David Beardsell and Max Sutcliffe, and also to the fine printing done by publisher Reed New Holland. Just looking carefully at all the photos is also very revealing, as often the captioning contains more useful information. Do you know what a tree gnawed by bush rats until it fell over looks like?

And I must also comment on Jones’ and Elliot’s prose, which is clear and concise but also familiar and entertaining. This is not a dry scholarly text. You should read the first few book chapters, and also the introduction section of each subsequent chapter, rather than just use it as a reference book. You will come across such gems as:

“Outbreaks of pests are frequently a problem in new gardens but their incidence lessens as the gardens become established”

Maybe that’s known and obvious to some, but it wasn’t to me and the explanation of why that occurs is equally revealing.

What is depressing is finding how many serious plant pests and diseases only arrived in Australia within the last 10-15 years. Ash whitefly, now a real problem on trees in Adelaide was first found in 1998; cotton mealybug which attacks many native and exotic Malvaceae species breached our biosecurity sometime after 2009; and of course the dreaded and dreadful myrtle rust that arrived from South America in 2010 has the potential to cause major ecological damage to our Australian flora, including species extinctions in the long term.

With the spread of the soil-borne root-rotting fungus Phytophthora cinnamomi in many home gardens (and even, I learn in PDA&AofAP, to the home of the dinosaur tree, the Wollemi Pine where three trees have died) I also am reminded of the crucial importance of plant hygiene including the cleaning and disinfecting of tools, shoes and vehicles. [Note: for those who employ gardeners or any kind, I would ask about their plant hygiene regime before letting them anywhere near your plants.] For those already wrestling with this problem disease, PDA&AofAP’s Appendix 1 has a handy list of both susceptible and mostly resistant native plants.

Know your remedies
As I read PDA&AofAP, I realised that I really didn’t understand the difference between many pesticide and fungicide sprays, including what they’re are made from, and how they work. Nor did I know that bacterial spore suspensions, like many caterpillar sprays, (eg Dipel) should only be used in the late afternoon or on cloudy days as they degrade quickly in UV light. Or that neem oil is a repellent that disrupts pest feeding and growth, rather than a killer.

It’s a book for Australian plants but also many exotics
Although PDA&AofAP says it’s for Australian plants, most of the exotic pests that attack Australian plants also attack a wide range of exotic hosts. And among the Australian native pests and diseases, while some are specific to Australian plant hosts like the grevillea looper caterpillar, many will happily chomp through any plant, refusing to be nationalistic in their tastes. Of course there will be a few exotic plant specific pests and diseases you won’t find in PDA&AofAP but not many.

Do you really need a book  – can’t you just look these up on the Internet Of Things?
The short answer, yes, you do…as no, you can’t. You could describe some symptoms and the plant and try internet searching for a hit, either in web or images. But my own experience tells me that’s time consuming; mostly inaccurate as you can’t adequately discount results from other countries that confuse the issue; and often the information is just not online. Which is what I found a couple of years ago trying to work out what was attacking my Vitex. A very rigorous online search turned up nothing – but there it is in PDA&AofAP – the Vitex leaf beetle.

Vitex leaf damage

Vitex leaf damage to my tree, which I had to remove in the end as I couldn’t control the damage.

Are there any drawbacks about this book?
Of course, as a home gardener growing both, I immediately want it to be about exotic plants as well as Australian native ones. But that’s a totally unfair criticism as it was never intended to be.

However, I’d like a better Index. Using the book to track down several of the problems I’ve had with native plants I’ve grown, I expected to see entries in the Index that would help me find them in the book. For example, I’ve had several wattles with galls but there’s no Index entry for either ‘Acacia galls’, or ‘Galls, Acacia’. There are many mentions of pests in the text that don’t appear in the Index. eg Syzygium mite gall has a photo and some text in the Galls chapter, but it’s not listed in the Index under Syzygium. Indexing is specialised skill and an expensive part of producing a reference book but I hope that the publishers invest more in that for a future edition.

My overall assessment
At $45.00 RRP, this book is relatively inexpensive addition to the Australian gardener’s library and one that will return much, much more, both academically and also in feeling like you’re more in control of what’s going on in your garden. Knowledge is power! ★★★★

Pests, Diseases, Ailments and Allies of Australian Plants‘ by David Jones, Rodger Elliot and Sandra Jones. Published by Reed New Holland 2015. ISBN 9781877069970, 260mmx 185mm paperback with PVC covering, 440 pages.

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Catherine Stewart

About Catherine Stewart

Award-winning garden journalist, blogger and photographer; writer for garden magazines and co-author of 'Waterwise Gardening'; landscape designer turned landscape design judge and critic; compulsive networker and lover of generally putting fingers in lots of pies. Particularly mud pies. Creator, curator and editor of GardenDrum. Sydney, NSW.

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