The Living World Within Roses
Adult lunate ladybird feeding
Last year this time I did an article "The Living World within Conifers" and thought that it would be appropriate to have a look at one of my favourite plants, the rose. If you are passionate about roses, you should also be passionate about all the wonderful things roses bring to your garden. First forget about the so-called "destructive" pests like flower beetles and African (American) bollworm and have a close look at the world of insects that might be present on your roses.
Assassin bug sucking juice from
During the first 2 weeks of May this year I spent a little more time identifying the insects on my rose garden. Allowing aphid populations to build up (literally caked round the young flower stems) a multiple number of very interesting insects made their appearance. Due to the aphid infestation, the populations of two main species of beneficial ladybirds started to build up. With the honeydew secreted by the aphids came many flower fly species as well as many other nectar lovers including parasitic and predatory wasps. The flies in return attracted one of their main predators the robberfly. All these insects together attracted many spider species like the flower crab and sac spider. The presence of the assassin bug specie sucking the life out of an aphid made me jump with joy, but as things happen in nature even beneficial insects like ladybirds has someone slightly higher up in the food chain. Round the middle of May there were hardly any aphids left due to a very high population of ladybirds that build up and just to annoy me, I caught an assassin bug sucking the daylight out of a ladybird.
Blowfly on rose stem (honeydew
excreted by aphids attracts flies)
Adult amber ladybird feeding
on an aphid
After this exercise I have come to the conclusion that roses, especially when infested with aphids, should be very good companion plants with vegetables like tomatoes. I have never seen the rose aphid on my tomatoes. Aphid infested roses near your vegetable patch should attract most of your very important pollinators like flies, butterflies and parasitic wasps, as well as predators like praying mantis and ladybirds. Once their populations build up on the roses you create an excellent breeding ground for them. As soon as certain insect pests start showing on your vegetables they will move towards this new hunting ground.
Flower crab spider waiting
patiently for prey
Robberfly with catch of the day;
a fly species.
At all times, when you see such a healthy combination of insects on your roses, avoid the spraying of especially broad spectrum insecticides designed to kill beetles. Handpick flower and CMR (blister) beetles during daytime and in the case of the chafer beetle; venture out at night with a flashlight to collect them. Select pesticides that are more pest specific. Red spider mite for example can be controlled with Ludwig's Rose Spider Mite or Grovida Red Spider Mite Wise with no harm to the wonderful world of natural controls. Botanical oil formulations like Margaret Roberts Organic Insecticide, Efekto Rape Oil and Biogrow Vegol (which contain canola oil) will kill all very small bodied insects like aphids and red spider mite with no or minimal harm to bigger bodied predators like ladybirds, praying mantis, assassin bugs and chameleons . African bollworm (previously known as American bollworm) can be controlled with a biological insecticide Margaret Roberts Bological Caterpillar Insecticide or Grovida Caterpillar Wise for controlling the young active feeding larvae with no harm to any form of natural enemy of caterpillars. Ludwig's Insect Spray+ contains canola and garlic oil combined with natural pyrethrum which can kill small and bigger bodied insects on direct contact will control a very broad spectrum of insects but no secondary poisoning will occur. The choice of pest control is yours. Personally I have chosen the more balanced route where I tolerate aphids on my roses as an important food source for my natural predators and parasites. Aphids do not kill roses and if you are patient enough, a healthy population consisting of various parasitic and predatory insects can clean out your roses within 10 to 14 days, the average interval between applications of most insecticides.
For more information send an e-mail to or visit my website www.gardencare.co.za
Snail and Slug Control in Harmony with Nature / The Living World Within Roses / Inaugural IPM-endorsed training courses will commence this month. / Garden Plants Perfect for Attracting Beneficial Insect Parasites and Predators / The Living World of Conifers / Winter Garden Care: To Spray or Not to Spray? / Spiders and Pesticides / Cold Blooded Wildlife: The Gift of Nature / Predatory Ladybirds: Nature's Solution to Aphid Control
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Garden care advice to consumers on the use of agricultural remedies ( pesticides).
Biopesticide product development for registration with Act 36 of 1947, Department of Agriculture.
Garden talks and editorial contributions to consumer magazines.
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