Transcript

Trap Crops · Hydroponics Daily

0:00
Hi, welcome back to Hydroponics Daily with me, Dr. Russell Sharp.
0:03
And the topic for today is trap crops.
0:07
And these are different to carnivorous plants.
0:11
So carnivorous plants are plants that have evolved to get nitrogen specifically
0:18
from animals, catch animals, and then decompose them.
0:22
Trap crops are plants that
0:25
you plant within your crop to sort
0:28
of control a pest but it's not it's not
0:32
evolved as to as like a carnivorous plant so
0:34
the examples are the classic example is radishes where
0:38
you plant them in the soil next to your maybe carrot
0:42
crop and then the wire worms that
0:45
would normally attack your carrots go into the radishes the
0:48
low value plants and then you destroy the
0:51
radishes and then by doing so you control the
0:54
wireworms that's the theory however a lot
0:57
of the evidence for trap crops
1:01
is not there there's very little proof and so
1:04
you do have to take reports with a pinch of salt unless they've come from a
1:08
scientific study other examples include mustard so mustard seed is very cheap
1:14
and you plant that next to cabbages which is related they're both in the brassica
1:18
family and then the idea is that the caterpillars go onto the mustard instead of the cabbages.
1:23
Obviously this is a gamble because.
1:27
Two things. The mustard might be attracting more caterpillars into your area
1:31
by giving off chemicals to say, I'm a brassica, come and eat me.
1:35
And then also, if they feed on the mustard and you don't kill the mustard before
1:41
the eggs emerge and new adults butterflies appear, then you've actually added
1:48
to your pest and disease problem.
1:49
And then also you've crowded out your growing environment, increased the humidity,
1:53
and you might get other diseases that live in the brassica family.
1:56
So it's it's it's a highly debatable one it's linked
1:59
to companion planting however trap
2:02
crops are normally not grown for for the
2:05
harvestable crop if you planted a load of radishes in your carrots
2:08
and they weren't attacked by wireworms then you could obviously harvest
2:11
them but that's not the main aim of a trap crop there are
2:15
other examples of where certain weed species can
2:18
exude chemicals that cause nematodes to
2:21
hatch and but then the
2:24
plant the weeds themselves are then resistant to attack by the
2:27
nematodes or where the the the
2:31
pest can't complete its life cycle on the plant
2:34
that caused them to germinate in the first place
2:37
to to hatch so as
2:40
i say it's a poorly studied area there is another example of and this is probably
2:45
more linked to hydroponics is where you can put you can germinate potato tubers
2:52
so sea potatoes in your in your area grow area and they will attract.
2:59
Pests sap sucking pests and then you simply take those potato tubers and throw
3:04
them away so you could you could do this with sea potatoes or equally you could
3:07
just get some potato tubers from the supermarket germinate them in your grow
3:11
room and then that would attract things and then the things that you would be
3:14
looking for would be things like this it's.
3:17
Mainly used on mealy bugs but mealy bugs
3:19
are not tend to be a problem in hydroponics because they don't
3:23
they can be excluded from a filter but you
3:27
could try this with aphids it would be a good one to
3:29
try and then obviously remove the potato potato
3:33
tubers before the the aphids start to
3:36
produce young that would
3:39
be the key thing obviously you can another there
3:42
is opportunities to use carnivorous plants as trap
3:45
crops so you could but they would be expensive maybe
3:48
you've got a way of growing hydroponic carnivorous plants well you
3:52
could put some in your other hydroponic crops to
3:55
catch other insects however there
3:59
are you know with varying degrees of success would a
4:01
venus flytrap catch a spider mite or a thrip
4:04
probably not it's more looking for blue bottles and and
4:07
big flies but there are some interesting examples and
4:11
the one that i want to highlight is a
4:14
plant from south america called philcoxia and
4:18
philcoxia is interesting because it produces an
4:21
extra set of leaves underground and these
4:24
are sticky and they attract nematodes and then
4:28
there's an enzyme on these leaves called.
4:31
Protease and that breaks down the protein into amino
4:34
acids that the plants can use as a source of nitrogen
4:37
so that's an interesting one
4:40
philcoxia is a very obscure plant though from south america i
4:42
don't even if you google it there aren't many
4:46
pictures of it but if you're struggling with nematodes in your
4:49
garden perhaps that's that we want to look at so
4:53
trap crops not super specific to hydroponics but
4:56
certainly something that people will have played around with you know.
4:59
Using plants to attract pest and disease marigolds
5:03
is an example of for aphids that's the classic example planting
5:06
marigolds around your edible plants
5:09
to attract aphids and then killing the marigolds before the aphids can grow
5:13
up you've you've got a couple of issues you know obviously you have to you have
5:17
to kill the plants off before it's actually just increasing the pest numbers
5:21
and the the other issue is are these trap crops,
5:27
attracting pests to your grow environment you know
5:30
i don't like mix mixing my grow
5:33
environment so if i've got if i'm growing one plant like
5:36
black grass in a growing environment i don't want tomatoes
5:39
and eggplants in there because they could attract
5:42
pests i just wanted to keep it to one so potentially
5:46
for that reason you could be attracting more to your area and
5:50
you know more plants in an area more things that can
5:52
go wrong and issues but do you have you used
5:55
a trap crop have you found a success let me know on dm me find me on social
6:01
media that's been hydroponics daily for today truck crops and as all good podcasters
6:06
say smash that like and subscribe button and make sure you're i'm getting a
6:12
phone call i'll have to leave it there thank you very much.