0:00:02 > 0:00:04Hello and welcome to The A To Z Of TV Gardening.
0:00:21 > 0:00:25Everything we're looking at today begins with the letter I.
0:00:26 > 0:00:29We start with an in-depth look at the creatures who,
0:00:29 > 0:00:32especially during the warmer months, arrive in our gardens
0:00:32 > 0:00:35in their millions and play a role in them
0:00:35 > 0:00:37that's as crucial as our own.
0:00:37 > 0:00:39Yes, I is for insects.
0:00:39 > 0:00:42And, to get things started, let's join Chris Packham
0:00:42 > 0:00:47and bask in the beauty of the Great British butterfly.
0:00:47 > 0:00:51You know, we have over 50 species of butterflies in the UK
0:00:51 > 0:00:54and they've been living alongside us for thousands of years
0:00:54 > 0:00:58in our woodlands, field margins, parks and gardens.
0:00:58 > 0:01:02But butterflies are not just pretty faces. Oh, no.
0:01:02 > 0:01:06Their private lives can be both complex and fascinating.
0:01:06 > 0:01:09Take the Large Blue, for example.
0:01:09 > 0:01:11The caterpillars hatch out
0:01:11 > 0:01:14and feed on wild thyme, but then
0:01:14 > 0:01:17they trick a species of ant into taking them
0:01:17 > 0:01:19into their nest underground
0:01:19 > 0:01:22and here they eat the ants' own grubs
0:01:22 > 0:01:25before emerging again the following year.
0:01:25 > 0:01:29You've got to agree, butterflies are pretty amazing.
0:01:35 > 0:01:37Sadly, in recent years,
0:01:37 > 0:01:41Britain's butterflies have been in serious trouble.
0:01:41 > 0:01:45And the statistics are fairly sobering.
0:01:45 > 0:01:48Well, it's really bad news for British butterflies.
0:01:48 > 0:01:50Over the past three decades or so,
0:01:50 > 0:01:51three quarters of our
0:01:51 > 0:01:53butterfly species have declined,
0:01:53 > 0:01:54so that's a massive loss
0:01:54 > 0:01:56for many different species.
0:01:56 > 0:01:59Five species have become extinct in Britain completely
0:01:59 > 0:02:02and many others are threatened with extinction.
0:02:04 > 0:02:08To understand why our butterflies are suffering,
0:02:08 > 0:02:11we have to uncover their complex and fascinating lives.
0:02:13 > 0:02:17To do that, we have to start at the beginning.
0:02:17 > 0:02:20Female butterflies are notoriously
0:02:20 > 0:02:21picky about exactly where
0:02:21 > 0:02:24they lay their eggs.
0:02:24 > 0:02:28Some butterflies only breed on a single species of plant.
0:02:28 > 0:02:33White admiral, for example, only breeds on honeysuckle.
0:02:33 > 0:02:35But most of them actually breed
0:02:35 > 0:02:38on plants from a single family.
0:02:38 > 0:02:40Purple emperor breeds on sallows,
0:02:40 > 0:02:42which are a type of willow.
0:02:42 > 0:02:44- RICHARD:- They're very choosy, these butterflies,
0:02:44 > 0:02:47and that makes them very sensitive. As soon as that plant has gone,
0:02:47 > 0:02:50then they go extinct in that place straightaway.
0:02:50 > 0:02:51They live very fast lives,
0:02:51 > 0:02:54so they respond very quickly to these changes.
0:02:55 > 0:02:59CHRIS: And the reason they are so fussy? Well, it's because of these.
0:02:59 > 0:03:03The key to a butterfly's success is getting the right
0:03:03 > 0:03:07food plants for their hungry caterpillars and, unfortunately,
0:03:07 > 0:03:10these plants have been disappearing from our countryside.
0:03:12 > 0:03:15- RICHARD:- The big problem that our British butterflies have faced is
0:03:15 > 0:03:19the loss of traditional ways that we manage our farmland and forests.
0:03:19 > 0:03:24They're now increasingly restricted to small pockets of habitat,
0:03:24 > 0:03:28small islands in a sea of otherwise inhospitable terrain -
0:03:28 > 0:03:31might be intensive farmland or housing, roads and so on.
0:03:31 > 0:03:35And they really need to be able to move through the landscape.
0:03:36 > 0:03:40CHRIS: But with that landscape changing so fast and such specific
0:03:40 > 0:03:43and different needs, it's no wonder that
0:03:43 > 0:03:45they've found it difficult to cope.
0:03:47 > 0:03:50But there is a simple solution to their complex problem.
0:03:50 > 0:03:55Understand the species and then make space for its needs.
0:03:55 > 0:03:58We're lucky. We know a lot about butterflies in Britain,
0:03:58 > 0:04:00probably more than any other country in the world.
0:04:00 > 0:04:02They respond so quickly to change
0:04:02 > 0:04:06and we can reverse some of these declines.
0:04:08 > 0:04:11The perfect example is the Heath Fritillary.
0:04:11 > 0:04:13Its food plant, Common Cow-wheat,
0:04:13 > 0:04:16grows in sunny, woodland glades.
0:04:16 > 0:04:18Now, when traditional forestry methods stopped,
0:04:18 > 0:04:23the clearings covered over and the butterflies came close to extinction.
0:04:23 > 0:04:26But by simply changing back to the original practices,
0:04:26 > 0:04:29in woodland in Kent the Heath Fritillary
0:04:29 > 0:04:32is now thriving once again.
0:04:32 > 0:04:36It's not all bad news for butterflies, by any means.
0:04:36 > 0:04:39The truth is that they live in a bit of a different dynamic,
0:04:39 > 0:04:41almost a different dimension to us
0:04:41 > 0:04:45and their populations yo-yo up and down,
0:04:45 > 0:04:48depending on weather cycles
0:04:48 > 0:04:51and what's happening with their habitats
0:04:51 > 0:04:53and they can boom or bust.
0:04:53 > 0:04:57We want to see far more boom.
0:04:57 > 0:04:58# Boum
0:04:58 > 0:05:01# L'astre du jour fait boum
0:05:01 > 0:05:02# Tout avec lui dit boum
0:05:02 > 0:05:05# Quand notre coeur fait boum-boum... #
0:05:19 > 0:05:22Now, let's join Joe Swift,
0:05:22 > 0:05:25who's been having pest-related problems on his vegetable plots.
0:05:27 > 0:05:30It's a relaxed summer's day at the allotment.
0:05:30 > 0:05:34A bit of harvesting, bit of weeding, bit of watering,
0:05:34 > 0:05:37maybe putting a few bits and pieces in and taking some out.
0:05:37 > 0:05:39But, the exciting thing is, I've got
0:05:39 > 0:05:41an entomologist coming up here today.
0:05:41 > 0:05:43What's one of those?
0:05:43 > 0:05:45An entomologist, Mark, is Bugman.
0:05:45 > 0:05:48Bugman. You've heard of Batman, you've heard of Spider-man,
0:05:48 > 0:05:51we've got Bugman coming up, because there's a few bits and pieces
0:05:51 > 0:05:54eating some of my crops, so I thought I'd get him up and have a look.
0:05:54 > 0:05:56Right, I just want to show you my peas,
0:05:56 > 0:05:58cos I'm not sure what this is at all.
0:05:58 > 0:06:01There's a couple that have died out and I was wondering
0:06:01 > 0:06:05whether it was early stem damage, the stem got damaged or something.
0:06:05 > 0:06:08But now they're going a little bit yellow around this patch.
0:06:08 > 0:06:10I suspect it's actually a virus.
0:06:10 > 0:06:12Looking at some of these plants, you can still see
0:06:12 > 0:06:15- the mosaic symptoms on the leaves. - Oh, yeah, OK.
0:06:15 > 0:06:17This will be a virus that's transmitted by aphids, greenfly.
0:06:17 > 0:06:22I did have some blackfly and some greenfly here and I've used this.
0:06:22 > 0:06:23It seemed to have got rid of it,
0:06:23 > 0:06:26but maybe the virus had already been spread.
0:06:26 > 0:06:29This is just an organic soapy solution.
0:06:29 > 0:06:30OK, fatty acids.
0:06:30 > 0:06:32Yeah, and it did the job.
0:06:32 > 0:06:35Yeah. Looking at these plants, I can't see any aphids on there,
0:06:35 > 0:06:37so it looks like you have done a really good job of it.
0:06:37 > 0:06:40- But you will need to keep on top of those aphids.- OK.
0:06:40 > 0:06:41What about next year?
0:06:41 > 0:06:45Well, these seed are likely to contain the virus as well,
0:06:45 > 0:06:49so don't use the seed for planting next year's plants.
0:06:49 > 0:06:52Just keep a very good eye on the plants early on
0:06:52 > 0:06:54and try to keep on top of the aphids.
0:06:54 > 0:06:57Cos it's possible that there's a reservoir of the virus
0:06:57 > 0:06:59- somewhere else on this allotment. - OK, right.
0:06:59 > 0:07:01It would be a real shame to get rid of them.
0:07:01 > 0:07:04- cos I'm getting loads of peas off them at the moment!- Absolutely.
0:07:04 > 0:07:08Who's this fellow? He looks like he's after your sandwiches, rather than my brassicas.
0:07:08 > 0:07:10This is a larvae of a moth of some sort.
0:07:10 > 0:07:12It could be a tiger moth of some sort.
0:07:12 > 0:07:14But it's certainly not a problem to your allotment.
0:07:14 > 0:07:16OK, I'm glad, cos he's so beautiful,
0:07:16 > 0:07:18I wouldn't want to damage him or her.
0:07:18 > 0:07:22This will be feeding on some of the weeds around, maybe bramble.
0:07:22 > 0:07:24How do you know which are the goodies and which are the baddies?
0:07:24 > 0:07:28Yeah, that's tricky, but I think it's just experience, really.
0:07:28 > 0:07:30If you watch your plants, you'll recognise the caterpillars
0:07:30 > 0:07:33that are eating your vegetables and the ones that aren't.
0:07:33 > 0:07:36Is it a problem? If something is eating your caterpillars, is it bad?
0:07:36 > 0:07:38I've just squashed one between my thumb and forefinger.
0:07:38 > 0:07:42Is that a bad thing to do, or is that perfectly legitimate in the world of the allotment?
0:07:42 > 0:07:46I think if you're 100% certain that that species is eating your plants,
0:07:46 > 0:07:49then it's a safe and effective way of getting rid of them.
0:07:49 > 0:07:52But certainly don't go around killing every caterpillar you see,
0:07:52 > 0:07:54because things like this aren't a problem.
0:07:56 > 0:07:58Right, on my sage.
0:07:58 > 0:08:02I've had a bit of problem at home with mildew and stuff,
0:08:02 > 0:08:04but this doesn't look like mildew at all.
0:08:04 > 0:08:06That's the feeding damage of the sage leafhopper.
0:08:06 > 0:08:09- Do you see them on here? - Feeding damage? Oh, right. OK.
0:08:09 > 0:08:12- Do they hop?- Yeah. - Oh, they do hop?- Yeah.
0:08:12 > 0:08:14They hop nicely, actually.
0:08:14 > 0:08:16Is there anything else I should be worried about?
0:08:16 > 0:08:18It looks perfectly edible, this sage.
0:08:18 > 0:08:21No. All that is, really, is a little bit of leaf damage.
0:08:21 > 0:08:23They feed on plant sap,
0:08:23 > 0:08:26so what they're doing is tapping into the cells,
0:08:26 > 0:08:28sucking out the contents, and you end up with
0:08:28 > 0:08:30these little necrotic areas,
0:08:30 > 0:08:31which is basically empty cells.
0:08:31 > 0:08:33OK. It's not affecting the taste?
0:08:33 > 0:08:36- They're not nicking all the tasty bits of my sage?- No.
0:08:36 > 0:08:38What have you got there?!
0:08:38 > 0:08:40I've brought my pooter along
0:08:40 > 0:08:43which is what an entomologist uses to catch insects.
0:08:43 > 0:08:45Oh, this is exciting!
0:08:45 > 0:08:47You basically suck down the tube and
0:08:47 > 0:08:48- the insects end up in the pot.- OK.
0:08:51 > 0:08:53Oh, it's completely silent...
0:08:53 > 0:08:55- There they are.- And there they are,
0:08:55 > 0:08:57in your little jar. Hopping around.
0:08:57 > 0:09:00If you look at these under a microscope, they're really pretty.
0:09:00 > 0:09:03- They are very beautiful, aren't they?- Yeah.
0:09:03 > 0:09:06- They won't cause you too much damage.- OK, fine.
0:09:06 > 0:09:08So I'm going to leave those little fellas there.
0:09:08 > 0:09:10We'll release these later.