Ruud Kleinpaste: Mealybugs and Scale Insects - tricky pests for the summer

One of the rottenest pests gardeners get on their plants are Pseudococcus longispinus, or any of its close relatives. 

Longispinus derived from the word meaning “with a long spine or tail”, so we’re talking about the Long-Tailed Mealybug. Mind you, there are other rotters that don’t look anything like these mealybugs – a variety of scale insects do the same kind of damage, which you really don’t want to see in the garden. 

All these insects feed by plumbing their mouthparts into the veins of the plants where they extract honeydew, a sweet sap that contains Nitrogen, which makes the young bugs grow. 

Ah! Yes, the group of sap-sucking bugs is the only invertebrate cohort that can be called “bugs” in the naming game of Entomology! 

They ingest the sap and poop out honeydew. But their numbers (huge groups) and activities are debilitating for your plants, causing yellowing and ill-thrift, plus black sooty mould all over the place. 

The sooty mould is a fungal cover that feasts on the sweet honeydew – you can always tell the suckers because of the sooty mould! 

To identify these mealy-insects you’ll need to have a good eyesight. The way to start your identification is to look for dense, white patches of silk all over your plants, especially over the leaves and on the stems. 

If you scrape off the fluffy white deposits, you’ll get to the insects hiding underneath that fluff. Big ones and smaller ones all living together out of the rain and out of the sun. 1-4 mm in size. 

They eat a massive range of plants, both edibles and ornamentals. 

The spines and tails give the game away – there are also droplets of honeydew in amongst the mix. 

Scale insects are a different-looking critter. These pests are characterised by looking like randomly shaped and coloured pustules on the stems and leaves of the host plant. 

Often the “caps” of the scale insects are pretty hard; the actual insects live under the caps, often in perfect protection. 

Control of mealy bugs and scale insects is difficult. The white fluffy silky stuff makes the bugs waterproof – water-based sprays cannot penetrate through their skin, unless you use some systemic insecticide that is taken up by the plants. Groventive is such a systemic spray but read the label and you find it cannot be used on edible crops! 

Conquerer Oil and Neem Oil are non-systemic treatments that will give the immature Mealybugs a run for their money (suffocation and inhabit their feeding from the plant). But it will require regular spraying (once a week) until all bugs have starved to death or suffocated. Thoroughly cover the infested plant – and don’t forget the underside of the leaves too! 

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Episode Transcript

Speaker 1 (00:07):
You're listening to the Saturday Morning with Jack Tame podcast
from News Talks that Be Rude.

Speaker 2 (00:13):
Time passes our men in the garden.

Speaker 3 (00:15):
Good morning, A very good morning to you tricky piece
in the garden this morning. Yeah, but first I'm going
to deal with some tricky language. I'm sorry. I mean,
you know, I don't know if you've noticed, but there
is an enormous nonsense in the marketing language. Yes, I'll
give you an example. We and watch this because this

(00:36):
is becoming big and I bet it's going to be controversial.
There are these these politicians that talk about we now
have an a political ecosystem.

Speaker 2 (00:48):
Oh yeah, why it's not an ecosystem, because an ecosystem exactly.

Speaker 3 (00:54):
But an ecosystem is wonderful. It is collaborative, it's not competitive,
it's all the other things. This is what I a
you got it yet, And also not only an econo
ecosystem political ecosystem, but also things like what we're talking
about today, we're talking about bugs. Well, the funny thing
is that bugs are a very specific group of insects

(01:16):
that are the true bugs, and and all the others
are literally invertebrates, you know, the ones without a backbone
and all that sort of stuff. So I thought, let's
talk about bugs.

Speaker 2 (01:29):
Okay, yeah, merely bugs in particular. We have Honestly, I
just feel like this is the problem with the indoor
plant at applace in particular. We are just always fighting
the media bugs.

Speaker 3 (01:40):
Yeah, mellibug. And so there's two. They're basically similar, scale
and sets and media bugs in the same group, and
they are a pain in the bumb to actually control,
if you like. So let's have a look at that first.
So they were they're really nasty things. The first thing
they both do, both melli bugs and and and the
scale and sects, they stick their their their their watching

(02:04):
the call of the things that front to suck up
the juices from the plants, from the veins of the
leaves and from the plants. And basically what they then
do is they poop out the honeyjew the sweet sap, which,
by the way, is a nice word for the turd
in nature. Yeah you know, got it. You have to
told you that before anyway, So this is how it works.

(02:26):
They get stuff out of the plant and they pop
it out as honeydew. And on top of the honeyjew
grows a black sooty mold, which is a fungus that
actually makes it kind of go away. But it shows
you now what you're looking for if you are if
you have these problems, if you get a black stuff
on the top, it's always a sap sucking bug that

(02:48):
does it. There's a couple of few, quite a few
of those particular varieties. And so as you said, inside
where you are with your house plants, absolutely, but outside,
especially in Auckland with its nice relative humidity, you get
heaps of them too, and it is really a pain
in the bum to get rid of. Yeah, so here

(03:10):
we go. What do you do? You use materials that
are systemic, if you like, and that you can use.
I'll give you an example. Grow Ventive is a really
good material, but if you read the label you say
you cannot be used. You can be using that on
edible crops because it's not very good for us to

(03:31):
eat something that has been sprayed with grow ventive. Yeah,
this is a really important one. Then you have the
famous kneem oil we quite often talk about.

Speaker 2 (03:40):
Yep, I've got any oil at our place. That's what
we do.

Speaker 3 (03:43):
I know you do. And conquerer oil, which is a
similar sort of thing, and here comes the thing and
you see it on those photos that are sent to Libby.
If you've got very young meai bugs or very young
scale insects, it takes time for them to grow, and
when they lay their eggs, the babies come out literally
not that long after. And that means you have to

(04:05):
reapply that particular material said I mentioned, to grow ventive
in the Conqueror on anymore, say every week, maybe every
ten days or so. And if you do that consistently,
you can do it, mate, you can.

Speaker 2 (04:18):
I don't know. I feel like we've been fighting a
fight that's lasted a lot longer than ten days at
our place. Road. It's like whack them hole with the
merely bugs at our place. But like you say, you've
just got to be fastidious. Hey, thank you, sir. Have
every weekend. Catching in very soon.

Speaker 1 (04:32):
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