GREEN­LIFE MAT­TERS

The good bugs

Go Gardening - - Editorial | Contents -

In­ever needed an ex­cuse to grow flow­ers, but a cou­ple of sum­mers ago I de­cided to de­vote a large sec­tion of my vege gar­den to bees and other ben­e­fi­cial in­sects. Aim­ing for flow­ers from early spring though till late au­tumn, I planted a mix­ture of easy care peren­ni­als and an­nu­als suit­able for dry cli­mates.

The peren­ni­als in­cluded he­le­nium, echi­nacea, globe this­tle, Rus­sian sage, cat­mint and salvias. Bor­der­ing the path, I planted dif­fer­ent va­ri­eties of thyme. For ex­tra blue ac­cents I planted an­nual Echium, blue tansy (Phacelia), corn­flow­ers and bor­age. I also grew yel­low fox­gloves, scented sweet peas, and tow­er­ing sun­flow­ers.

An­nu­als make great gap fillers while al­low­ing ex­per­i­men­ta­tion with some­thing new each year. In the first year of my bee gar­den I tried zin­nias in bright in-your-face colours, which turned out to be great for pick­ing and kept flow­er­ing well into May. In the sec­ond year I went for a softer colour op­tion with dwarf yel­low cos­mos.

Suc­cess is hard to mea­sure but the bees seemed de­lighted. But­ter­flies were plen­ti­ful too. I had no prob­lems with pol­li­na­tion and will hap­pily credit my bee gar­den for the bumper crops of pump­kins and cu­cum­bers. And also for a dis­cernible re­duc­tion in aphids and white­fly, espe­cially in the sec­ond sum­mer af­ter plant­ing. Ei­ther way, I en­joyed the flow­ers and all the life they at­tracted and it felt good to think that my ef­forts were go­ing some way to help bio­di­ver­sity. At least in my small cor­ner of the world.

PLANT­ING FOR POL­LI­NA­TORS

As a gar­dener who’s far too lazy to pol­li­nate her pump­kins by hand, I am very grate­ful for na­ture’s helpers.

For pure plea­sure it makes sense to plan a gar­den that al­ways has some­thing in bloom, but in do­ing so we also pro­vide a re­volv­ing food sup­ply for all man­ner of pol­li­na­tors. Bees en­joy the nec­tar and pollen from a wide range of flow­ers but they’re par­tic­u­larly par­tial to blue and pur­ple, yel­low and white. Gen­er­ally, the sim­ple old fash­ioned flow­ers have the most ac­ces­si­ble and plen­ti­ful pollen for bees. Many have mark­ings that are sign­posts for their pol­li­na­tors.

Be­ing bee friendly gives me a per­fect ex­cuse to be un­tidy. Vege plants that turn to flower and or­na­men­tals that are over­due for dead-head­ing pro­vide food and hid­ing places for ben­e­fi­cial in­sects. Na­ture loves a messy gar­den.

Of course, the ben­e­fits of plant­ing to sup­port na­ture go be­yond the back­yard. With­out in­sects for pol­li­na­tion we’d be miss­ing a huge chunk of the world’s food sup­ply, not only for hu­mans but all the other an­i­mals that de­pend on fruit and seeds in their diet. Pol­li­na­tors are in de­cline and con­cerned gar­den­ers world­wide are mak­ing con­certed ef­forts to help them.

PEST PA­TROL

Keep­ing a close watch on the pest bugs in my gar­den, I’m also aware of the ones who prey on them. It’s ex­cit­ing to spot a lacewing or a hover fly, or what I hope is a par­a­sitoid wasp. Or to zoom in on what I now know to be the pre­his­toric look­ing larva of a la­dy­bird. Th­ese vo­ra­cious preda­tors of com­mon pests de­serve to be en­cour­aged!

In New Zealand we have thou­sands of species of tiny par­a­sitic wasps. Smaller than ants, th­ese guys don’t sting. In­stead they lay eggs in­side other in­sects, more specif­i­cally their eggs, lar­vae or pu­pae. When the wasp lar­vae hatch from their egg they con­sume their prey, pu­pate and emerge as new adult wasps. There are par­a­sitic wasps known to prey on aphids, cater­pil­lars, white­flies, codling moth lar­vae. Name the pest and there is likely a par­a­sitic wasp that preys on it! New species of par­a­sitic wasp are con­stantly be­ing dis­cov­ered. Usu­ally each par­a­sitic wasp species at­tacks just one kind of pest. They oc­cur nat­u­rally in our en­vi­ron­ment but many have also been brought into New Zealand as bi­o­log­i­cal con­trol agents for crops. Find out more about this on www.bio­force.co.nz.

My favourite par­a­sitic wasp dis­cov­ery in­volved a strange look­ing struc­ture I found on a leaf of my bay tree. I placed it in a closed con­tainer while I tried to work out what it was. The next day the lid of my con­tainer was cov­ered in black dots. The dots turned out to be hun­dreds of tiny adult wasps (easy to see un­der a low power mi­cro­scope) which had hatched from pu­pae in­side the corpse of a green looper cater­pil­lar. Grue­some but true. But how did one tiny wasp lay that many eggs? It turns out that this par­a­sitic wasp does a thing called polyem­bry­ony whereby a sin­gle egg can di­vide it­self into mul­ti­ple em­bryos, which in this case amounts to 10002000 fu­ture wasps. Af­ter hatch­ing, the lar­vae wait un­til the cater­pil­lar is fully grown be­fore they con­sume it. The cater­pil­lar even­tu­ally dies as it spins its co­coon - mak­ing a cosy habi­tat for the wasp lar­vae to pu­pate in.

Par­a­sitic wasps and bees are close cousins. Like bees, the adult wasps seek food from flow­ers and are pol­li­na­tors. By plant­ing bee friendly flow­ers we are also likely to at­tract th­ese minis­cule gar­den he­roes. Par­a­sitic wasps are said to like yel­low marigolds, also laven­der and the herbs fen­nel, rose­mary and dill.

Scar­ily, it seems that the world is only just wak­ing up to the mas­sive con­tri­bu­tion preda­tory in­sects make to­wards keep­ing pest in­sects in check. We are all too aware about the hu­man health risks of pes­ti­cide use. Ben­e­fi­cial in­sects are also at risk. Prod­ucts (both nat­u­ral and syn­thetic) that kill bad bugs also kill good bugs. In­te­grated pest man­age­ment in­volves care­ful mon­i­tor­ing and mind­ful use of preven­tion and con­trol op­tions to min­imise the pres­sure we put on na­ture when grow­ing our food.

BOOST­ING SOIL LIFE

Some bugs are so small that we can only see them with the most pow­er­ful microscopes. They’re called micro­organ­isms or mi­crobes and they in­clude the fungi and bac­te­ria that live in our soil. Up to a bil­lion of them live in just one tea­spoon of healthy soil, sci­en­tists say. With new species be­ing dis­cov­ered all the time, much is yet to be dis­cov­ered about th­ese micro­organ­isms and their ecosys­tems. What is known for sure is that they per­form some very use­ful func­tions in the soil. For ex­am­ple, micro­organ­isms are ac­tively in­volved in sup­ply­ing nu­tri­ents to plants. They also play an im­por­tant role in dis­ease preven­tion.

When we add com­post or or­ganic ma­nure to our gar­dens we’re adding fu­ture hu­mus, the black stuff that is or­ganic mat­ter bro­ken down com­pletely to its most sta­ble form. Hu­mus is where micro­organ­isms live. So when we add or­ganic mat­ter to our soil we are sup­port­ing soil life and bio­di­ver­sity. It’s amaz­ing to think how many good bugs there might be in each bar­row load of com­post! Be in to win Yates ben­e­fi­cial in­sect flower seed. De­tails on

Bees are par­tic­u­larly par­tial to sim­ple old fash­ioned flow­ers in shades of blue, pur­ple, or yel­low.

LEFT: Echi­nacea RIGHT: He­le­nium FAR RIGHT: Old fash­ioned flow­ers in the Hob­bit gar­den at the 2017 NZ Flower and Gar­den Show

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