life cycle of aphids https://youtu.be/HVTitHBwpN0
bugs for bugs , predators https://bugsforbugs....ur-pest/aphids/
using predators are prob best used as early as poss after discovery
can still be the best choice in flower though , even if they don't totally eradicate
for the future , it's all bout Brix level , the measuring of sugar in the leaves & how that relates to plant health
& pest resistant's
INSECTS AND BRIX
First of all, one must understand at some level that insects do not attack healthy plants.
Many people know this instinctively, but few have been told this explicitly. It is for this reason
that knowing your leaf Brix levels is crucial to knowing your crop, whatever you may be growing.
High Brix (14 and above) means not just that insects will not attack a given plant but that they
will not even be attracted to the plant. In short, pest insects will pass over a high Brix field.
The converse is also true. Insects are very attracted to low Brix plants (6 and below). Unfortunately,
if one uses insecticides to keep insects off plants, then it takes longer to realize this truth due to the
insect indicators being repelled or killed. If you leave the insects alone, they will indicate to you the
relative health of your plant. Now a logical, and seemingly heretical, conclusion to be drawn from this
is that insecticides are totally unnecessary for protecting high-Brix plants. Financially speaking, excessive
inputs reduce profit. Eliminating insecticides will increase a farmer’s profit — this should be your goal.
But if the only important Brix value to know is “12,” then what exactly is the purpose of having the other numbers?
What types of information can be gleaned from Brix values of fourteen, or nine, or even five? For those who want
to know something about their crop — immediately, right there on the spot — without having to send a sample
away to some far-off laboratory, then you should be Brix-testing on your farm.
Higher Brix plants: 8+
Once a plant reaches a leaf Brix of 8, the secondary plant metabolites have really started to kick in and natural
resistance begins. In my experience, Homopterous insects, such as aphids and scales, lose interest in the plant
that obtains a value of 8 Brix. In fact, it is relatively common for me to spot these insects on plants below 6 Brix.
When a plant reaches 8 Brix, the aphids lose interest, but other insects can and will move in to feed on the plant.
In certain circumstances, the presence of aphids can be an indication that only a part of the plant is below 8 Brix.
Diseases characterized by physical “plugs” that prevent the flow of nutrients through phloem and xylem tissue are
often manifested in trees by dead or dying branches. Insects will focus their feeding on these weakened branches
and ignore nearby branches with seemingly healthy leaves and/or stems. It is for this reason that different parts of
the same citrus tree can display different leaf Brix readings when Citrus Greening takes hold, and even more so
during drought conditions, when plugging of the vascular tissue is prevalent.
When plants ascend the leaf Brix ladder and reach between 8 and 11 Brix, insects metaphorically “fall off” the plant
because the plant has a “sword and shield” that protects itself from insect predators. As a general rule, and although
exceptions occur, sucking insects will not tolerate 8 Brix or higher. Chewing insects that eat the roots or leaves directly,
such as caterpillars, grasshoppers, and beetles, will start to lose interest in eating a plant once the plant reaches 10 or 11 Brix.
I have witnessed grasshoppers taking bites out of 12-Brix leaves and then flying off the plant. I have also witnessed
immature caterpillars of the Fall Webworm stop eating the leaves of a pecan tree once the Brix is increased to 12. As a result,
these caterpillars will form a dense clump and then slowly die of starvation within inches of healthy growing pecan leaves.
Virtually no insects will attack a plant at 12 Brix; this is why this figure is tossed around so commonly among growers.
Now variability is a hallmark of Nature. Fluctuations between Brix readings can and do occur throughout a growing season.
Even if maintaining Brix levels in a given crop, it is not unusual for the leaves to fluctuate 1-2 Brix from one week to the next.
It is for this reason that the safest place for your plants to be is at 14 Brix or above. In this way, one may be relatively secure
that natural fluctuations do not take your crop below 12 Brix where it may become differentially attractive to various insect pests.
Edited by itchybromusic, 12 August 2020 - 09:04 PM.