yes neem cake would def help , there's a little bit of neem oil left in the crushed neem seed ( neem cake )
also making a kelp & neem cake tea , neem for the bugs , & a lill nutrients , & kelp for the plant health boost
you could also add aloe vera for more plant boosting & the saponins in aloe can work as a pesticide
fungus gnats eat fungus , in coco the only place you might find fungus to eat
is attached to the roots of the plant , we all know it as mycorrhizal fungi
hence the idea fungus gnats eat roots = no they eat fungus attached to roots
the root damage is collateral from fungus consumption
in soil especially living soil , there are or should be plenty of fungus for the gnats to consume
it's still possible for the gnats to eat fungus attached to roots but there should be plenty of options
other than root fungus for them to consume
imho best to work on "out competing" unwanted pests which is the exact opposite to what most
recommend = let the soil or top soil dry out , this is most likely good thinking if you are in a synthetic
system but not so good for the living soil growers , drying out the soil kills or forces dormancy
on the microorganisms , these soil dwellers are growing & protecting your plant & need a constant
moisture level to thrive & keep there territory & food source protected , need to be careful with moisture
cos over moistening removes oxygen & changes conditions in the soil , by doing this another bunch of
microorganisms start to thrive , some will be good but most will be bad
i say mulching is good as it helps to keep that soil moist for the soil dwellers to keep the nutrient cycling happening
as they consume the mulch layer as well as what was mentioned above with protecting there turf
over watering is bad as it changes conditions to be not suitable for beneficial organisms & depletes there power
to protect the plant & there turf
IPM is very important especially growing indoors where you loose half the soil food web from not being outdoors
gnats can be in bags of soil brought from stores that store the bagged soils outdoors like bunnings do
but allot of the time gnats come in to the grow room on you , your outside playing with the dog in the backyard
then you walk in to your grow room bringing a bunch bugs in with you , more so if the dog comes in as well
so be aware you could be the problem
spaying neem or using predictor bugs like carbcon mentioned are both good ideas just not at the same time
as the neem might take out some good dudes as well as the bad ones
using essential oils like rosemary as a pesticide & thyme oil as a fungicide , saponins in aloe as mentioned
you can use potassium silicate for it's boosting & protecting qualities as well as EM-1 soil drench & foliar sprays
all these things can help protect your plant & should be used as part of everyday growing as prevention
don't wait to see bugs b4 trying to control an infestation , be preemptive with your Integrated Pest Management
From the University of Waikato, New Zealand is this helpful article on the how & why Neem products function.
Neem protects itself from the multitude of pests with a multitude of pesticidal ingredients. Its main chemical broadside is a mixture of
3 or 4 related compounds, and it backs these up with 20 or so others that are minor but nonetheless active in one way or another.
In the main, these compounds belong to a general class of natural products called "triterpenes"; more specifically, "limonoids."
So far, at least nine neem limonoids have demonstrated an ability to block insect growth, affecting a range of species that includes some
of the most deadly pests of agriculture and human health. New limonoids are still being discovered in neem, but Azadirachtin, Salannin,
Meliantriol and Nimbin are the best known and, for now at least, seem to be the most significant.
One of the first active ingredients isolated from neem, azadirachtin has proved to be the tree's main agent for battling insects. It appears to
cause some 90 percent of the effect on most pests. It does not kill insects - at least not immediately. Instead it both repels and disrupts their
growth and reproduction. Research over the past 20 years has shown that it is one of the most potent growth regulators and feeding deterrents
ever assayed. It will repel or reduce the feeding of many species of pest insects as well as some nematodes. In fact, it is so potent that a mere
trace of its presence prevents some insects from even touching plants.
Azadirachtin is structurally similar to insect hormones called "ecdysones," which control the process of metamorphosis as the insects pass from
larva to pupa to adult. It affects the corpus cardiacum, an organ similar to the human pituitary, which controls the secretion of hormones.
Metamorphosis requires the careful synchrony of many hormones and other physiological changes to be successful, and azadirachtin seems to
be an "ecdysone blocker." It blocks the insect's production and release of these vital hormones. Insects then will not molt. This of course breaks their life cycle.
On average, neem kernels contain between 2 and 4 mg of Azadirachtin per gram of kernel. The highest figure so far reported - 9 mg per g - was measured in samples from Senegal.
Although thousand-year-old Sanskrit medical writings mention neem's usefulness, the tree's exciting potential for controlling insects has only recently become clear.
Neem's ability to repel insects was first reported in the scientific literature in 1928 and 1929. Two Indian scientists, R.N. Chopra and M.A. Husain, used a O.001-
percent aqueous suspension of ground neem kernels to repel desert locusts. Not until 1962, however, was the real significance demonstrated. That year, in field
tests in New Delhi, S. Pradhan ground up neem kernels in water and sprayed the resulting suspension over different crops. He found that, although locusts landed
on the plants, they refused to eat anything, sometimes for up to 3 weeks after the treatment. Furthermore, he noted that neem kernels were even more potent than
the conventional insecticides then available and that neem's repellency was as important as its toxicity. In neighboring insecticide-treated fields, for instance, the
insects also died, but not before consuming the crops.
Neem's insect-growth-regulating (IGR) effects were independently observed in England and Kenya in 1972. In England, L.N.E. Ruscoe, at that time an employee
of the ICI Company, tested Azadirachtin on insect pests such as cabbage white butterfly (Pieris brassicae) and cotton stainer bug (Dysdercus fasciatus) and noted
IGR effects in each case. The Azadirachtin was provided by D. Morgan, a Keele University chemist who had been the first to isolate Azadirachtin. In Kenya that
same year, K. Leuschner, a German graduate student working at the Coffee Research Station in Upper Kiambu, observed that a methanolic neemleaf extract
controlled the coffee bug (Antestiopsis orbitalis bechuana) by growth-regulating effects. Most fifth-instar nymphs treated with the extract died during subsequent
molts and the few that survived to adulthood had malformed wings and thoraxes.
Neem's fecundity-reducing effects were first recorded by R. Steets (another graduate student) and H. Schmutterer in Germany. Applying methanolic neem-kernel
extract and Azadirachtin to the Mexican bean beetle (Epilachna varivestis) and the Colorado potato beetle (Leptinotarsa decemlineata) they found that females
almost stopped laying eggs. Some females had been completely sterilized, and the effect was irreversible.
Another feeding inhibitor, Meliantriol, is able, in extremely low concentrations, to cause insects to cease eating. The demonstration of its ability to prevent locusts
chewing on crops was the first scientific proof for neem's traditional use for insect control on India's crops.
Yet a third triterpenoid isolated from neem is Salannin. Studies indicate that this compound also powerfully inhibits feeding, but does not influence insect molts.
The migratory locust, California red scale, striped cucumber beetle, houseflies, and the Japanese beetle have been strongly deterred in both laboratory and field tests.
Nimbin and Nimbidin
Two more neem components, Nimbin and Nimbidin, have been found to have antiviral activity. They affect potato virus X, vaccinia virus, and fowl pox virus.
They could perhaps open a way to control these and other viral diseases of crops and livestock.
Nimbidin is the primary component of the bitter principles obtained when neem seeds are extracted with alcohol. It occurs in sizable quantities - about 2% of the kernel.
Certain minor ingredients also work as antihormones. Research has shown that some of these minor neem chemicals even paralyze the "swallowing mechanism"
and so prevent insects from eating. Examples of these newly found limonoids from neem include DeacetylAzadirachtinol. This ingredient, isolated from fresh fruits,
appears to be as effective as Azadirachtin in assays against the tobacco budworm, but it has not yet been widely tested in field practice.