How to prevent and control pests and diseases in an organic garden? These key technical points must be mastered
I kept saying I would write a “pest control article”, but because the chance of pests when growing at home is not high, I rarely have the opportunity to take photos of pest damage. So far I have only photographed red spider mites and aphids. Even whiteflies did not pay a visit this time, let alone leaf miners. So I am very sorry that there are very few self-taken photos of pests and diseases. Some pests I only encountered in the first year I started growing, so I have never collected enough of my own photos and can only show them with detailed hand drawings. There are 3 pages of hand drawings.
Does having few pests mean that insects do not come near my balcony? No. Care is a very important process. In fact, the emergence of pests is very closely related to weather conditions. For example, the generally dry weather this spring created a good opportunity for aphids to grow. So my aphids produced as many as 3 generations in spring alone.
And this process of pests appearing is often very sudden. One day while watering, you suddenly find the stems and leaves covered with aphids. If you do not take measures to crush or kill the insects that day, then on the second and third days, aphid reproduction enters its peak and they will pile up. Because the excrement of aphids after sucking the sap of leaves is sweet, it will also attract ants to appear. So aphids not only harm the plants themselves; their follow-up harm is also very great. But aphids are actually the least harmful type of pest among plant pests.
Prepare green and safe sprays - pest and disease control for an organic garden
I kept saying I would write a "pest control article", but because the chance of pests when growing at home is not high, I rarely have the opportunity to take photos of pest damage. So far I have only photographed red spider mites and aphids. Even whiteflies did not pay a visit this time, let alone leaf miners. So I am very sorry that there are very few self-taken photos of pests and diseases. Some pests I only encountered in the first year I started growing, so I have never collected enough of my own photos and can only show them with detailed hand drawings. There are 3 pages of hand drawings.Does having few pests mean that insects do not come near my balcony? No. Care is a very important process. In fact, the emergence of pests is very closely related to weather conditions. For example, the generally dry weather this spring created a good opportunity for aphids to grow. So my aphids produced as many as 3 generations in spring alone.
And this process of pests appearing is often very sudden. One day while watering, you suddenly find the stems and leaves covered with aphids. If you do not take measures to crush or kill the insects that day, then on the second and third days, aphid reproduction enters its peak and they will pile up. Because the excrement of aphids after sucking the sap of leaves is sweet, it will also attract ants to appear. So aphids not only harm the plants themselves; their follow-up harm is also very great. But aphids are actually the least harmful type of pest among plant pests. Red spider mites are the same. In fact, they are not a kind of spider. Their scientific name is spider mite, visible to the naked eye, but much, much smaller than aphids. If you do not pay attention, you will not even notice small red dots on the back of leaves. Their appearance on the leaf surface is dense small dots. Red spider mites survive by sucking chlorophyll. After the chlorophyll on the leaf surface is sucked by numerous red spider mites at the same time, yellowing and drying characteristics appear. At the same time, if not controlled, red spider mites reproduce recklessly. They can complete one generation in about a week. Spider webs will appear between stems, with red spider mites crawling on them. So red spider mites can be considered a stubborn pest that easily makes a comeback.
There is another equally stubborn pest that basically occurs at high frequency in summer: whiteflies (see the hand drawing). One reason whiteflies are difficult to control is that they are very strong fliers, so unlike aphids and red spider mites, which move slowly and can be effectively controlled by crushing with your hands, with whiteflies, basically when your hand reaches over to crush them, they may immediately fly away.
The flying ability of whiteflies is related to the amount of waxy powder on their bodies, which is also why they are called "whiteflies". When they are young, there is not much waxy powder on their bodies, so their flying ability is not strong and they can only make short-distance flights. But when they become adults, because the amount of waxy powder on their bodies increases and the covering becomes thicker, their flying ability increases significantly.
Generally, the probability of whiteflies on self-sown plants is very low. They basically appear on potted plants bought in summer. So if you cannot avoid buying potted plants, be sure to check whether there are small white insects resting on the back of the leaves. Or when you look, if you find that originally resting small white insects fly out, then it is basically whiteflies. Even if it flies away, it is very likely to have already laid eggs on the back of the leaf.
There is another pest that lays eggs and survives in leaf veins: the leaf miner (also called map insect, see the hand drawing). It generally easily occurs on peas and nasturtiums. The methods for dealing with leaf miners are not right, and organic sprays cannot completely penetrate into the middle of the leaf. If you do not want to use chemical agents, then the best method is to remove the diseased leaves.
Some people will ask, then how can pests also appear on plants you sowed yourself? How can you try to avoid pest harassment as much as possible?
Apart from some flower lovers buying relatively large potted plants, because nursery management cannot be as careful as at home, they very easily carry viruses, pests, and pest eggs. Even for plants you sow yourself, it cannot be completely guaranteed that pests will never appear, but the quantity and probability are much, much lower than for purchased potted plants. This is also why I always recommend that everyone sow and take cuttings themselves.
The soil in which we grow plants includes garden soil, peat soil, various prepared nutrient soils, and so on. In fact, no matter how finely packaged the finished soil is, if it has not been truly thoroughly sterilized before packaging, it is very easy for it to carry insect eggs. Therefore, in the instructions for imported large-package peat soil, it is emphasized that the peat soil has undergone thorough high-temperature sterilization to ensure it does not carry insect eggs. However, after all, few flower lovers will buy the original 300L packaging. More often, they buy repackaged peat soil online, so that guarantee of not carrying insect eggs becomes invalid. During handling and contact with air, it will more or less be contaminated, so there is a possibility of carrying insect eggs.
Similarly, even if you buy original packaged sterilized peat soil yourself, we will not use it all up at once, especially balcony gardeners. The leftover peat soil, because of storage conditions (the original packaging is vacuum packaging), including the effects of temperature and humidity, if sealed tightly, easily produces moisture inside, causing the originally dry and sterile peat soil to become damp, so instead there is a risk of mildew and pathogens. Therefore, when storing peat soil, we must be careful not to tie it completely tight, and leave small gaps for proper air circulation. But with gaps, there is a risk of small insects getting in to lay eggs. So no ordinary home storage method can completely prevent the soil from always maintaining the quality it had in the original packaging. Therefore, if you are ready to start the path of gardening, pests will definitely accompany you. Even if you were originally a person very afraid of seeing bugs in various forms, in this process, you will definitely train yourself.
In addition to soil possibly carrying insect eggs, during the growing process, if small insects fly by and stop on the soil surface or plants to lay eggs, or bring bacteria and insect eggs they picked up elsewhere onto your plants, that is also a very important transmission route. So for us, the key to prevention and control is to frequently and carefully observe whether your plants are suffering from pest damage, especially the back of the leaves, where insect eggs and pests easily gather. Pests hiding on the back of leaves and laying eggs on the back of leaves is an innate self-protection mechanism. Because in the open air, the plant itself will be washed by dew and rain, and the front of the leaf directly receives sunlight, which is not suitable for the hatching of insect eggs, and the hatching success rate will be greatly reduced. So laying eggs on the back of leaves is both hidden and unable to be rained on, will not be washed away, will not be dried out by the scorching sun, and can likewise suck the sap of the leaves.
Therefore, when we spray organic sprays, we must remember to spray from the back of the leaves. Because the effectiveness of self-prepared organic sprays is not as fierce as agents with added chemical ingredients. There is indeed a chemical agent on the market that can kill when sprayed from the front and also from the back, but precisely because it can kill from both front and back, this shows that its toxicity is unusually strong. When choosing insecticides for non-edible plants, you can consider choosing it. But if you, like me, grow edible herbs, vegetables, melons, and fruits, then to be responsible for your own health, you must never use chemical agents. You can buy organic sprays on the market, or you can prepare organic sprays yourself.
Regarding the formulas for self-prepared organic sprays, flower lovers keep asking, and I keep answering, but I really have never discussed it in such detail. So in this blog post, I will very thoroughly publish 3 organic sprays with different effects and pest control formulas, hoping they will be helpful to everyone:
1. Two sprays: garlic olive oil spray & all-purpose organic spray
2. Plant fungicide
3. Eggshell method for preventing mollusks
First let us look at the production process pictures: (because there is a lot of content, there are 3 pages, respectively in the introductions to the 3 organic protection methods)
Explain in detail:
1. Sprays
Garlic olive oil spray
Materials:
Olive oil 5ml
Garlic 1tsp
Laundry detergent 1tsp
Method:
1. Crush the garlic into paste, put it into a spray bottle together with 500ml water, laundry detergent and olive oil, and shake well.
2. Spray 2-3 times a day on the leaf surface and the back of the leaves.
Note: Because of the self-protection mechanism of insect eggs, they are generally wrapped in a protective film. This protective film can be penetrated by chemical agents, but organic sprays cannot take effect. So organic sprays cannot kill insect eggs. Therefore, after discovering pest damage, you must spray continuously for 3 days, 2-3 times a day, to ensure that after the insect eggs hatch they are immediately killed by the organic spray. Otherwise, if you spray only once, the adults are killed, but new larvae hatch again, and it still cannot achieve a thorough insect-killing effect. Therefore, once you spray an organic spray, you must spray continuously for 3 days to consolidate the effect.
The left picture shows the situation after spraying garlic olive oil spray, and the right picture shows the situation before spraying:
Some flower lovers have also asked, what is the reason for adding these 3 ingredients?
Because the viscosity of oil will obstruct the respiratory system of insects, garlic has the effect of repelling and paralyzing the insect nervous system, and laundry detergent water can damage the surface of pests and cause them to dehydrate.
Then why use olive oil?
Olive oil is used because it is not greasy and its viscosity is not high. Otherwise the leaves will be greasy and oily, and highly viscous oil will clog the stomata on the leaf surface, so the leaves cannot breathe and will turn yellow and fall off. It is the same principle as when washing dishes: bowls used for olive oil are very easy to wash clean, while other oils need hot water to be washed clean. This is also the reason olive oil is healthy.
All-purpose organic spray
This is a relatively "all-purpose" insect-killing spray, and it is very convenient to make, because it uses liquid soap, and the kind of liquid soap we use to wash our hands is fine.
If you do not use liquid soap, you can also replace it with soapy water. The principle is the same, it is just that liquid soap is more convenient to use. It can disrupt and penetrate the cell membranes of insects, causing pests to dehydrate and die. However, the key to using soapy water or liquid soap is: never make the concentration too high, otherwise the plants will be killed along with them.
This formula also uses a relatively special plant-based insecticidal raw material: tomato leaves. In fact, tomato leaves contain several toxic alkaloids and are a natural insecticide, especially effective against aphids. Potato leaves also contain toxic alkaloids, but tomatoes are not grown in winter and potatoes are not grown in summer. So they can exactly serve as plant-based insecticidal raw materials for winter and summer: use tomato leaves in summer, and potato leaves in winter.
Materials:
Liquid soap 1tbsp
Water 1L
Garlic 3tbsp
Ginger 3tbsp
Chili (do not use sweet pepper) 50g
Tomato leaves 30g
Boiling water: the amount required is enough to completely cover these raw materials
Method:
1. Put all the raw materials in a small pot and cover with boiling water
2. Leave overnight
3. Filter out the residue
4. Put the filtrate, water and liquid soap into a spray bottle
5. Shake well and spray on the leaf surface and the back of the leaves.
Note: All homemade sprays should be used the same time in summer, or placed in the refrigerator, otherwise they will ferment.
2. Plant fungicide
Plants not only suffer from pests, they also get diseases. For example, gray mold, powdery mildew and black spot are very common plant diseases, and they are highly contagious. If you do not remove diseased leaves or take measures, then all the leaves on the plant will be infected, as if covered with a layer of white powder. Black spot is also a disease caused by fungi, and irregular black or dark brown round spots will appear on the leaves. Generally speaking, the previous method was to buy fungicides such as chlorothalonil and thiophanate-methyl and dilute them with water to spray on the leaf surface.
But although chlorothalonil is an extremely low-toxicity fungicide, it is still a pesticide after all. If we can make our own fungicide, then can we avoid even this low toxicity?
The answer is that fungicides are not difficult to make, and we can use materials on hand to prepare fungicides ourselves.
Materials:
Baking soda 1tsp
Water 1L
Soap flakes 1tsp
Method:
1. Put the baking soda, water and soap flakes into a spray bottle
2. Shake well and spray on the infected leaf surface
Note:
Leaves with severe infection must be removed. The leaves to be sprayed must still remain normally green, that is, just-infected leaves and uninfected leaves. The purpose of using this method is to control the range of infection, not to remove powdery mildew.
3. Eggshell method for preventing mollusks
Mollusks are what I fear most, such as slugs, snails and cutworms. Anything that wriggles around, once seen, will definitely make my hair stand on end. And mollusks also cause great damage to plants. For example, mollusks all like to chew leaves, so if you see large holes and gaps in leaves, you should quickly check whether they are present.
How can you prevent snails and others from climbing onto your balcony and settling there during humid weather?
There is a good method using crushed eggshells.
Materials:
Washed eggshells, any amount
Rolling pin
Method:
1. Put the eggshells into a container and crush them with a rolling pin (no need to pulverize)
2. Place the crushed eggshells on the soil to prevent mollusk invasion
This is a purely physical method with no impact on the environment at all. The reason the eggshells must first be washed is that unwashed eggshells will have egg white and other residue inside. If left in an outdoor environment for a long time, they will deteriorate and give off a bad smell, attracting the attention of small flying insects. And because crushed eggshells have sharp points, they will harm mollusks, so they do not like to cross any sharp, crushed eggshells. Spreading crushed eggshells on the soil can help block the invasion of these pests.
These are the most basic organic control methods. Of course, there are other organic protection methods. For example, some people use coffee powder, and some use milk to kill red spider mites (but personally I extremely do not recommend it, because milk produces heat and odor during the decomposition process, which is the so-called fermentation process. Instead, it will trigger other pests, and even seep into the soil and cause root burn).
In fact, there are many plant pests and diseases. A short article has limited content and cannot write everything clearly, especially regarding the fungus gnat control method that everyone has strongly requested, because the methods of producing, controlling and eliminating fungus gnats are relatively complex, and I plan to write a separate article to explain it. I hope today's content can be helpful to organic gardeners fighting on the front line of pest control~
Key technical points for pest and disease control after loquat harvest
At present, most loquats have finished fruiting. In addition to strengthening fertilizer and water management, pest and disease control is also an important prerequisite for ensuring whether the fruit trees can grow and develop normally and bloom and bear fruit later. The main pests and diseases after loquat harvest include leaf spot disease, pear psylla, mites, aphids, etc. Combined with recent weather conditions, the occurrence characteristics and key control technical points of these pests and diseases are introduced as follows.
1. Recent pest and disease occurrence 1. Loquat leaf spot disease: mainly manifests as gray spot, spot, angular spot and target spot symptoms, and occurs severely in rainy summer and autumn seasons. This disease not only damages leaves, causing them to turn yellow, wither, perforate and fall off, but also affects new shoot growth, thereby ultimately affecting photosynthesis. It generally occurs more severely from April to September. Recent investigation shows that in a few poorly managed orchards the disease is very serious, and 50% of the leaves have already fallen. If high-temperature and rainy weather appears later, it will be conducive to the occurrence of this disease, so the control of leaf spot disease cannot be ignored. 2. Pear psylla: In recent years, psylla has occurred commonly on loquat in our area, with multiple generations a year, and occurs more severely in dry seasons. After fruit harvest, its damage sites are mainly concentrated in the crevices at the base of leaf stalks, and it secretes mucus, with strong resistance to rain washing. In summer and autumn last year, pear psylla occurred relatively heavily on loquat, accumulating a large amount of insect sources; this year, affected by warm winter weather, with early drought and relatively high temperatures recently, it is conducive to the occurrence of psylla. Especially in orchards mixed or intercropped with pear trees, the occurrence of pear psylla is more serious. In severely affected orchards, the rate of new shoots with insects reached more than 80%. 3. Loquat false spider mite: false spider mite mainly damages new shoots and flower clusters, and is a common pest mite on loquat in our area; recent investigation shows the mite population is not high, but later high temperature and drought will make it occur more severely. 4. Other pests: yellow caterpillars mainly damage new shoots and leaves, and aphids damage new shoots. Control should also be strengthened after fruit harvest.
2. Comprehensive control technical measures: 1. Agricultural measures: strengthen fertilizer and water management, avoid excessive dryness or excessive moisture, enhance tree vigor, improve disease resistance, remove fallen leaves in time, and combine with fertilization to appropriately plow the soil to reduce the base number of pest and disease sources. Minimize intercropping, mixed cropping or relay intercropping of pear trees and loquat trees. 2. Physical control: install insect-killing lamps in the field, use light to trap and kill adult pests such as psylla and yellow caterpillars; use yellow boards to trap and kill aphids. 3. Biological control: when the number of mites per leaf is below 2, predatory mites can be used to control various mites; at the same time, plant and keep grass to attract natural enemies, and use the natural pest control ability of natural enemies to control major outbreaks of pests, such as using seven-spot ladybirds to control aphids. 4. Chemical control: seize the key period and apply pesticides for control. When the average number of mites per leaf reaches 3-5, apply 34% fenazaquin at 2000-2500 times dilution, or 2.4% abamectin at 3000 times dilution, etc. to control false spider mite; for psylla control, apply pesticide at the young larva stage, and the agent can be 25% thiamethoxam at 8000 times dilution or 2.5% psylla net for control. For leaf spot disease control, any one of tebuconazole, difenoconazole or hexaconazole can be selected for control.