Leaf Nibblers and Sap Suckers. (Supplementary Newsletter – May 2022.)

…………..Geoff Wilson was the speaker at the club’s March meeting and gave a very interesting and entertaining talk on “Leaf Nibblers and Sap Suckers”. Geoff has very kindly sent our secretary the following information relating to his talk, as a reminder for those who attended the meeting and for information for those who couldn’t join us on the evening.

Use pesticides only when they are really necessary. Most pests can be kept under control by cultivation techniques such as rotation of plants, destruction of plant residues, or hand removal of pests.

Encouraging natural enemies or even supplementing them with biological controls will reduce the need for spraying. Identify the pest correctly in order to apply appropriate control measures.

Know your enemy. If you do see something being attacked, first make sure you know which insect is doing the damage. Take a sample of the ailing plant to a reliable, knowledgeable garden centre and ask.

Kill ‘em with your bare hands. Or if you prefer, gloved hands. If you catch them early, a lot of pest infestations can be halted by hand. To get rid of snails and slugs, go out for a few moments at night with a torch and collect and kill them. You will quickly see their population diminish. A colony of aphids can be rubbed off with a cloth and soapy water.

Water early. Watering at night leaves a damp environment that encourages mould and mildew. It also inspires invasions from insects, slugs, and snails.

Rotate annual flowers and vegetables. Planting the same thing in the same place repeatedly makes it easier for insects that like a certain plant to get established.

Confuse insects with variety. Companion Planting solid beds of the same flowers or vegetables can encourage insects. If you mix up the plants, you literally mix up the insects because if the plant they love is next to one they hate, they don’t like to hang around.

Prune properly. Many bushes, trees, and other perennials are more vulnerable to insects if they have dead wood, or if their branches are so close together that they don’t get sufficient ventilation. So, make sure they are properly pruned. Sometimes an insect infestation can be stopped simply by pruning away the infected part.

Check your plants often. The earlier you spot an infestation the better. Take a good look at the backs of leaves, where many insects lay their eggs and begin their lives.

If you have a problem, first consider the least-toxic approaches.

Stick ‘em up. There are sticky, or syrupy substances on the market that you apply on a plastic or rubber band wrapped around trunks and stalks. Insects that crawl up the plant from the ground simply can’t get past these sticky barriers without getting stuck in them and dying.

Then try botanicals. If you must use a pesticide, choose a botanical first. They are made from plants rather than synthesized in a chemical factory. Having withstood the test of time, botanicals are safer than many synthetic chemicals.

They often contain one of the following active ingredients:

Pyrethrum, from a type of chrysanthemum, is a low-toxic choice, though some people might experience an allergic reaction. There are also synthetic pyrethrums that work the same way.

Less toxic chemical controls

Spray a dilute solution of fatty acids or liquid soap on affected leaves and rub the aphids off with your fingers. This will probably have to be repeated once or twice a week but as the plants age their tissue becomes tougher and less vulnerable to attack.

Plant resistant varieties– certain varieties are resistant to the viral diseases transmitted by aphids.

Be aware when using high Nitrogen synthetic fertilisers– these supply too much nitrogen to the plant allowing lush soft growth which is more susceptible to attack.

Companion planting – plant garlic cloves (just one or two) among rose bushes. An infusion of garlic crushed into water and sprayed on the aphids will also help remove them. Many herbs, such as hyssop, sage, dill, lavender and thyme discourage aphids if planted near to susceptible plants.

Plant a trap crop e.g. blackfly love nasturtiums which can be pulled out when they are infested.

Spray nettle spray – this is made from common stinging nettles and will help to control aphids.

Gather 224g (¹/₂lb) young nettles and soak in a bucket of water for a week. Strain and use undiluted as a control for aphids on roses and celery leaf miner. Add the mushy nettles to the compost heap.

Spray rhubarb spray– the oxalic acid in rhubarb leaves can help to control aphids, particularly on roses.

Cut 450g (1lb) rhubarb leaves, place in an old saucepan (the oxalic acid may damage one that you still use) with 1.1 litres (2pt) water and boil for half an hour, topping up as necessary. When cool, add 1 dessertspoon of soap flakes dissolved in 275ml (1/2pt) warm water. This acts as the wetting agent when added to the strained rhubarb liquid. Stir the mixture thoroughly and use undiluted as a spray. Rhubarb leaves are quite toxic so be careful to keep this away from children and pets.

Use elder spray – this is reported to be effective against aphids, small caterpillars and for mildew and blackspot on roses. The effective agent is hydro-cyanic acid, so use an old saucepan when preparing the spray.

Gather 450g (1 lb) leaves and young stems of elder prefer-ably in spring when the sap is rising. Place in the saucepan and add 3.3 litres (6pt) water. Boil for half an hour, topping up as necessary. Strain through old tights and use the liquid cold and undiluted. It will keep for three months if bottled tightly while still hot.

Coffee spray – This is one I swear by -Mix a good strong mix of black coffee and spray onto brassica whitefly, any aphid or caterpillars or slugs and snails.

Neem Oil Amounts For Insect Spray – Neem oil, from a tree, it is effective all stages of insect growth. Neem oil has antiviral, antibacterial, and antifungal properties.

For 1 litre of a 0.5 % dilution of neem plant spray you need:

• 5 ml neem oil
• 1-2 ml soap flakes
• 1 litre warm water

Chilli spray

Slice 500 grams of ripe chilli pods and place in a container then pour over 2ltrs boiling water. Cover and leave to stand for 4 to 5 days. Sieve the mixture and keep the liquid. Dissolve 30g of soap into this liquid Use  soap flakes.

How to use: Use as a spray, against most insects including caterpillars, aphids, flies, ants and mealy bugs. Apply once a week if there is no rain or two or three times a week if it rains. It is important to use this solution as a preventative measure.

If the concentration of the chilli solution is too strong, it can burn plant leaves. So it is important that the right strength is found by testing.

Garlic spray

Mince or finely chop three to four cloves of garlic, and add them to two teaspoons of paraffin oil. Let this mixture sit for 24 hours, strain and add the remaining liquid to half litre of water. Add one teaspoon of soap flakes. This mixture can be stored and diluted as needed. When you need to spray, use two tablespoons of the mixture added to one pint of water in a spray bottle. First test by spraying an inconspicuous part of the plant to see if your mixture harms it at all. If there are no signs of leaf damage after a day or two, it is safe.

TURMERIC

Without any exception, all insects dread turmeric. Plants treated with solution made out of turmeric and soap will make the leaf-nibblers and sap suckers quake on their perches. Add two teaspoons of turmeric powder to about a litre of warm water with a teaspoon of soapflakes (No not detergent powder), mix and allow to cool then spray over the infected plants.

Turmeric can also be used dry in powder form by dusting over the leaves of the plant to get rid of the Leaf nibblers.

NEEM OIL

Neem oil has many complex active ingredients. Rather than being simple poisons, those ingredients are similar to the hormones that insects produce. Insects take up the neem oil ingredients just like natural hormones. Neem  is particularly useful on sawfly larvae.

Neem enters the system and blocks the real hormones from working properly. Insects “forget” to eat, to mate, or they stop laying eggs. Some forget that they can fly. If eggs are produced they don’t hatch, or the larvae don’t moult. Obviously insects that are too confused to eat or breed will not survive.

Neem oil generally will not harm beneficial insects as it only really effects the nibbling and sucking  insects

Like real hormones, neem works at very low concentrations, in the parts per million range. A little neem oil goes a long way.

But this is not something that happens overnight. People use neem oil as an insecticide and expect everything to die instantly, because that’s what they are used to from chemical poisons. When that does not happen they conclude neem does not work. It does work! Give it time to work. It’s a much smarter way to deal with insect pests than to just kill everything.

The above article is reproduced with thanks and acknowledgement to its author Geoff Wilson.