Friday, May 6, 2011

The Savage Garden

We purchased some dwarf Alberta spruce this fall to use as our Christmas trees. There were quite small & we had them indoors & decorated for only the week of Christmas. Our aim is to grow them on the deck for a few years before finding homes for them in the yard.

I transplanted them into larger pots this spring & they put out a new flush of needles. But then I noticed something on the pots. Aphids!! I sprayed them off in the hopes they would just go away, but a week later they had returned.

Something I learned earlier this spring was that prey insects such as aphids, will require a few generations of presence in the garden to lure in the predator - so, in order to get rid of the aphids 'naturally' I would need to leave them be & hope ladybugs & other predator insects would somehow just find them.

Low & behold:
The Predator

Predatory ladybugs are usually found on plants where aphids or scale insects are, and they lay their eggs near their prey, to increase the likelihood the larvae will find the prey easily. Ladybugs are cosmopolitan in distribution, as are their prey. Ladybugs also require a source of pollen for food and are attracted to specific types of plants. The most popular ones are any type of mustard plant, as well as other early blooming nectar and pollen sources, like buckwheat, coriander, red or crimson clover, and legumes like vetches, and also early aphid sources, such as bronze fennel, dill, coriander, caraway, angelica, tansy, yarrow, of the wild carrot family. Other plants that also attract ladybugs include coreopsis, cosmos (especially the white ones), dandelions and scented geraniums.
The Prey:

They were circling the pot along the rim & then I noticed them all over the spruce itself & it is starting to drop needles!!

Plants exhibiting aphid damage can have a variety of symptoms, such as decreased growth rates, mottled leaves, yellowing, stunted growth, curled leaves, browning, wilting, low yields and death. The removal of sap creates a lack of vigour in the plant, and aphid saliva is toxic to plants. Aphids frequently transmit disease-causing organisms like plant viruses to their hosts.

I have isolated it from other plants in the hopes that the aphids won't jump ship & infest the rest up on the deck.

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