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Extra Floral Nectaries - have you ever seen them? · Hydroponics Daily

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Hello there and welcome back to
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Hydroponics Daily, your go-to podcast for everything soilless cultivation.
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I'm your host Dr. Russell Sharp and apologies in advance, I've got all the windows
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open, we're in a noisy environment but it's just too hot.
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It's 32 degrees Celsius here in the UK and that's way too hot to be closing
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yourself in a room with no fans or anything like that.
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So I thought today I'd talk about a really interesting subject.
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A botanical subject, it's extra floral nectaries
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and i would imagine most people
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haven't heard about these so i thought it'd be a good episode to
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talk about a fascinating botanical feature found on many plants
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and so these are little glands uh
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that can play a big role in plant defense insect attraction
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and even integrated pest management but
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what are they and how can hydroponic growers use them to
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their advantage so let's get into it extra floral
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neck trees or efns are nectar producing
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glands found outside of flowers so
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we're all used to flowers producing nectar for pollinators
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like bees and moths and things like this
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and pollen pollen and nectar being the two rewards that
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pollinators get however unlike floral neck trees
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which attack pollinators extra floral neck trees
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typically located on the they're located on the leaf
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petiole the the stalk on the
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end of the leaf the leaf blade so they might actually be
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on the leaf itself they can be on stems or they
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can be on bracts as part of a bract and bracts are specialized leaves associated
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with flowers talked about that in a previous episode and they secrete a sugar-rich
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fluid and the purpose isn't to the law of pollinators is to attract protective insects like ants,
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ladybirds or ladybugs if you're in North America and parasitic wasps.
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Let's just dive into them because some of those things you might think are not beneficial.
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We think of ants as being a pest in gardens and they can actually farm aphids,
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green fly, white fly, black fly on your plants and do them harm.
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They can eat your plants as well but in some cases plants
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can get them to eat pests and
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so that'd be good ladybirds obviously they eat loads
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of things loads of insects that are pests of plants especially their
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larvae and but the problem is is
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that things like ladybirds and parasitic mites and
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so predatory mites they can run out of food when there's no
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pests around and so things like extra floral neck trees can
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be a good source of food when there's no pests around it keeps the population
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up so it's not just the population crashes and dies
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especially in a grow room where you haven't got you know you don't want to keep
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on buying them and parasitic wasps these are not the yellow stinger wasps these
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are tiny microscopic wasps that are really good because every single pest of
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a plant there is a parasitic wasp species that will attack it and so you can
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help them by providing nectar for them.
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With extra flora nectaries, then isn't that fantastic and it'd be great for pest control.
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So they serve a couple of interesting roles, defense against herbivores by attracting
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ants and other predatory insects.
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You could also use them as a sign that
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a plant is drought stressed or there's water
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deficits because some plants produce more nectar under
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stress and maybe as an indirect defense
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signal so it's more you it's
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interesting that you produce more nectar under stress
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so you think it would be the other way wouldn't you that they
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would just turn off that nectar but for some reason they're producing more
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which is interesting so yeah well
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which plants have got extra floral nectaries well over 4
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000 species across more than 100 families plant
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families are known to have extra floral nectaries
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some some good examples that you might grow in your
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garden or in your hydroponic setup your grow room okra or
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okra ladies fingers very popular
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in america not very popular here in europe passion flower
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and passion fruit obviously very big
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in asia cotton very popular in
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america eastern europe asia has
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lots of extra floral nectaries we think of cotton as being
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this sterile crop that's grown with loads of pesticides but
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it doesn't have to be the case a third of all pesticides in the world are used
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on cotton which is a disgrace because it's a non-food crop and honestly leads
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to massive problems in the dry areas where it's grown because they build up
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and cause cancer you have cancer clusters in china and places like that where
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it's grown apologies some chav in your car has just gone past with a massive exhaust.
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Sunflowers sunflowers have got extra floral net trees and vetches
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lots of beans so vetches castor bean
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ricinus and normal broad
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beans things like this all the different types of beans and some tomatoes
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under stress or pest pressure can produce extra
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four net trees apparently i've never seen that but if you've
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ever seen that let me know they can be mistaken for
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other things so they can be mistaken for insect damage or
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sacks the remains of sap sucking insects they
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can be mistaken for fungal or bacterial infections when you get this sticky
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sticky goo especially bacterial infections you know you think of bacterial canker
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produces like an ooze like an amber coming out of the plants especially cherry
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trees and cherry trees have got extra floral nectarines so you might think that.
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The goo coming out of the extrafluoronectaries on the ptls is bacterial
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canker but the difference to know is that bacterial
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canker comes out of bark and extrafluoronectaries on
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cherry trees are on the ptl or
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near to the leaf pt on the
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leaf but near the ptl i used to grow a species a plant called prunus
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africana and that's really really prominent extrafluoronectaries you
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might mistake it for guttation we've talked about guttation in
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the past that's where positive root pressure under high
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humidity during the start early on in the day forces liquid
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out of the leaf margins whereas and that's
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normally an unwanted characteristic and whereas
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you do want your plants producing extra four nectarines
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so yeah extra four nectarines is
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a deliberate secretion and as we say it's nectar
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so it's high in sugars and it can be high in amino acids as
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well if you see ants patrolling young leaves
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and stems and stopping at small glistening dots so that's
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likely extrafluoronet trees at work so you
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can use them in hydroponics as natural attractants if you're going the crop
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some growers use extrafluoronet rich crops as insectary plants like interplanting
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okra in greenhouses to stimulate that that's a really good one i've never known
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anyone to do that but i'd be interested to try that interesting to grow okra
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anyway, because I like kronokra.
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It's a funny vegetable, isn't it? It's really sticky, and obviously,
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ladies' fingers looks like fingers.
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So, yeah, I think it might be a bit too cold in the UK for that,
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but it's 32 degrees Celsius at the moment, so who knows?
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Some of the disadvantages could potentially attract unwanted pests.
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Like certain ants. You've got to make sure that's in balance.
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It may produce a sticky mess in tightly controlled vertical systems if all this
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nectar was flying everywhere.
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So, I wouldn't imagine it's not much of a problem as long as you keep
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everything sterile and clean you've got to clean up every now and again haven't
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you uh you know if you're not cleaning up dust and
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things like this from your grow room it's very important so potential for
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growers reducing reliance on pesticides strengthening
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and making your beneficial insect population
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much more robust not going through feast and famine population
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explosion and then decimation and this serve as bio indicators of pest problems
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or even stress so lots of research going on about this could there'll be genetic
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enhancements and engineering plant resistance through this so especially in
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cotton legumes cherries okra plants with really big extra floral nectaries so um.
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That's extra-floronectaries. They're powerful, underutilised,
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but also not many people know about them. So they're tiny glands on your plants.
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If you have got okra, cherries, beans growing in your growing environment at
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the moment, passionflower, cotton, then have a look.
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Get a microscope or a hand lens and have a look.
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If you haven't got a hand lens, go onto the Utrema website. we've got
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led and uv hand
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lenses for sale at cost price because we
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we like you and we give them out to grow shops every now
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and again to help with that when anyone brings in a pest or
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disease problem into the grow shop so that's been
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hydroponics daily for today if you've got extra floral net trees if you're
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growing one of those crops or you know somebody who is then share
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this podcast with them and if this podcast has been shared with
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you then you owe that person a very cold icy drink
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and you could do me a favor if you could just screenshot
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your podcast provider here on your phone and then
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share it on social media and say i listened to this fantastic episode
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about extra floral net trees and i think you should too
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that would mean the world to me because that would help grow the podcast and
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increase its listenership thank you very much for listening today i'm going
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to go and have a very very cold soak with a hose in my back garden until tomorrow
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That's probably too much information. That's been Hydroponics Daily. Goodbye.