Common Pests and Diseases in Pear Tree Cultivation and Their Control Measures
Pest and disease management in pear orchards is also one of the most important aspects. In addition to keeping records of the species and damage caused by pests and diseases, as well as archives on the types, dosages, frequencies, and techniques of pesticide use, how to achieve rational pesticide use plays a major role in pest and disease control.
First, apply the right remedy for the problem. Choose the most suitable pesticide variety to control each pest and disease. Different pathogens and insects respond differently to the toxicity of the same chemical. In other words, every pesticide has a specific scope and target of control. For example, triadimefon can effectively control pear rust and powdery mildew, but its control effect on other diseases such as pear scab is very poor. Imidacloprid (Yibianjing) has a significant effect on controlling piercing-sucking pests such as aphids and planthoppers, but is ineffective against mites. Deltamethrin (Decis) is effective against pear fruit moth, aphids, pear psylla, and various caterpillars and slug moths, but is ineffective against mites.
In addition, the sensitivity to chemicals differs at different stages of the disease infection process. When fungal spores are germinating and invading the pear tree, they are more sensitive to chemicals, and the control effect is better; once the pathogen has invaded the fruit tree and established a parasitic relationship, and the fungus has developed into mycelium, its resistance to chemicals increases, and the control effect becomes poorer. Once fruiting bodies have formed, control becomes even more difficult, as with pear rust. Therefore, disease control should be carried out before the onset of disease or in the early stages of infection.
Second, apply pesticides accurately. The correct pesticide concentration refers to the most dilute concentration that can effectively control pests and diseases without causing phytotoxicity to pear trees. If the concentration is blindly increased, it will waste the pesticide, easily cause pests and diseases to develop resistance, and may also cause phytotoxicity to pear trees, poisoning of humans and livestock, and pollution of fruit and the environment; if too dilute, it will fail to achieve the purpose of control. There are many methods of applying pesticides. When applying, the correct method should be selected according to the damage characteristics of the target pest, the pesticide variety, and the formulation characteristics. For example, emulsifiable concentrates, wettable powders, suspension concentrates, aqueous solutions, and soluble powders can be diluted with water for spraying; powders and granules cannot be diluted with water for spraying. Spraying should proceed from inside to outside, from top to bottom, without missing any area or over-spraying, just enough to thoroughly wet the leaves without forming flowing droplets. The application rate is the amount of active ingredient of the pesticide per unit area. When controlling pear tree pests and diseases, attention should be paid not only to spraying branches, trunks, leaves, and fruit uniformly and thoroughly, but also to avoiding excessive application, especially when temperatures are high, as the liquid remaining on leaf surfaces can quickly evaporate water, causing the concentration to rise and potentially causing phytotoxicity to pear trees.
Third, apply pesticides safely. The safe use of pesticides mainly includes safety to humans, livestock, fruit trees, fruit, and natural enemies. When controlling pests and diseases in pear orchards, priority should be given to high-efficiency, low-toxicity, low-residue pesticides and biological pesticides, and pesticide use should be strictly controlled. Highly toxic and high-residue pesticides are strictly prohibited from being sprayed on fruit trees that have already set fruit. At the same time, the pesticides used must have the “three certificates” (pesticide registration certificate, production license, production approval certificate, and standard number). Before handling pesticides, applicators should understand the properties of the chemicals and the precautions for safe use, and take the necessary safety measures.
Finally, protect natural enemies. Strengthening biological control of pests and diseases is necessary for producing green, pollution-free fruit. In nature, there are many natural enemies of fruit tree pests and diseases, including parasitic ones such as Trichogramma wasps and Pteromalid wasps, predatory ones such as ladybugs and lacewings, and microbial natural enemies that cause disease in pests, such as Bacillus thuringiensis and Beauveria bassiana. These natural enemies have a powerful natural control effect on fruit tree pests and diseases. We should try our best to protect these natural enemies when carrying out chemical pesticide control.
1. Choose the appropriate timing of application. The best control period is when pests have reached the control threshold or the critical control period, and before natural enemies have become established. If there are many natural enemies in the orchard, pesticides should not be used or should be used selectively to facilitate natural enemy control of pests. For example, in the early stage of aphid damage, when natural enemies are few, chemical control should be used; in the later stage, when the species and number of natural enemies increase, as long as no economic damage is caused, pesticide use should be minimized to protect natural enemies.
2. Use more systemic or highly selective pesticides, and use fewer broad-spectrum or highly toxic pesticides. For example, in the early stage of mite infestation, specific, long-lasting acaricides should be applied to protect natural enemies. Broad-spectrum pesticides kill natural enemies while controlling pests. Since natural enemies have weaker reproductive capacity than pests, this can easily lead to outbreaks of pests. Choose the appropriate timing of application. The best control period is when pests have reached the control threshold or the critical control period, and before natural enemies have become established. If there are many natural enemies in the orchard, pesticides should not be used or should be used selectively to facilitate natural enemy control of pests. For example, in the early stage of aphid damage, when natural enemies are few, chemical control should be used; in the later stage, when the species and number of natural enemies increase, as long as no economic damage is caused, pesticide use should be minimized to protect natural enemies.
3. Choose appropriate application methods, such as seizing the opportunity of localized pest outbreaks to carry out selective treatment, reducing widespread application over large areas. For example, Decis is frequently used in production because it can kill a wide variety of pests, but Decis causes severe damage to natural enemies in pear orchards, and repeated comprehensive use can easily lead to mite outbreaks.
4. Choose appropriate pesticide formulations. For the same pesticide, granules and micro-granules have less impact on natural enemies, while emulsifiable concentrates and powders are more harmful to natural enemies. Choose appropriate application methods, such as seizing the opportunity of localized pest outbreaks to carry out selective treatment, reducing widespread application over large areas. For example, Decis is frequently used in production because it can kill a wide variety of pests, but Decis causes severe damage to natural enemies in pear orchards, and repeated comprehensive use can easily lead to mite outbreaks.
Precautions: rational mixing. Since multiple pests and diseases often occur simultaneously during a certain growth period of pear trees, pear growers frequently mix two or more pesticides in a certain ratio for spraying. However, pesticide mixing has strict requirements.
1. Pesticides of the same type with the same mode of action and control effect do not provide synergistic effects or broaden the control spectrum, so they should not be mixed.
2. Each pesticide in a mixture must not undergo changes in active ingredients after mixing, and the mixture must not reduce efficacy or cause phytotoxicity to pear trees. For example, mixing lime sulfur with Bordeaux mixture can easily cause phytotoxicity, and the control effect also decreases significantly.
3. The main target and occurrence stage of the current spraying must be clearly identified, and the effective pesticide or complementary pesticide for each control target must be determined.
4. If the toxicity of the mixed pesticide solution becomes highly toxic, it should not be mixed.
Clever Methods for Pear Tree Pest and Disease Control
Pear is a common fruit, sweet and juicy, and rich in nutrients. However, during pear tree cultivation, pests and diseases require timely treatment. So from which aspects should pear tree pest and disease control be approached?
First, apply the right remedy for the problem, and choose the most suitable pesticide variety to control each pest and disease. Different pathogens and insects respond differently to the toxicity of the same chemical. In other words, every pesticide has a specific scope and target of control. For example, triadimefon can effectively control pear rust and powdery mildew, but its control effect on other diseases such as pear scab is very poor. Imidacloprid (Yibianjing) has a significant effect on controlling piercing-sucking pests such as aphids and planthoppers, but is ineffective against mites. Deltamethrin (Decis) is effective against pear fruit moth, aphids, pear psylla, and various caterpillars and slug moths, but is ineffective against mites.
In addition, the sensitivity to chemicals differs at different stages of the disease infection process. When fungal spores are germinating and invading the pear tree, they are more sensitive to chemicals, and the control effect is better. Once the pathogen has invaded the fruit tree and established a parasitic relationship, and the fungus has developed into mycelium, its resistance to chemicals increases, and the control effect becomes poorer. Once fruiting bodies have formed, control becomes even more difficult, as with pear rust. Therefore, disease control should be carried out before the onset of disease or in the early stages of infection.
Second, apply pesticides accurately. The correct pesticide concentration refers to the most dilute concentration that can effectively control pests and diseases without causing phytotoxicity to pear trees. If the concentration is blindly increased, it will waste the pesticide, easily cause pests and diseases to develop resistance, and may also cause phytotoxicity to pear trees, poisoning of humans and livestock, and pollution of fruit and the environment. If too dilute, it will fail to achieve the purpose of control. There are many methods of applying pesticides. When applying, the correct method should be selected according to the damage characteristics of the target pest, the pesticide variety, and the formulation characteristics. For example, emulsifiable concentrates, wettable powders, suspension concentrates, aqueous solutions, and soluble powders can be diluted with water for spraying; powders and granules cannot be diluted with water for spraying. Spraying should proceed from inside to outside, from top to bottom, without missing any area or over-spraying, just enough to thoroughly wet the leaves without forming flowing droplets. The application rate is the amount of active ingredient of the pesticide per unit area. When controlling pear tree pests and diseases, attention should be paid not only to spraying branches, trunks, leaves, and fruit uniformly and thoroughly, but also to avoiding excessive application, especially when temperatures are high, as the liquid remaining on leaf surfaces can quickly evaporate water, causing the concentration to rise and potentially causing phytotoxicity to pear trees.
Control Methods for Pests and Diseases of Hongxiangsu Pear
During the cultivation of Hongxiangsu pear, we need to pay attention to controlling pests and diseases. Below, the editor shares with you the control methods for pests and diseases of Hongxiangsu pear.
I. Using Jiaduo insect-killing lamps to kill pests
Hongxiangsu pear fruit is susceptible to damage from pests such as fruit borers, stink bugs, and scarab beetles. These pests have the characteristic of moving quickly, making chemical control relatively difficult. Using Jiaduo frequency-vibration insect-killing lamps can kill more than 2,000 fruit borers, stink bugs, and other pests per night, with a killing effect of 70%, which can effectively control the above pests.
The Jiaduo frequency-vibration insect-killing lamp, on the one hand, has high technological content. It utilizes the phototaxis, wave, color, and scent characteristics of pests by setting the light wavelength within a specific range, using light at close range and waves plus color and scent at long range to attract adults. A frequency-vibration electric grid is installed outside the lamp for contact killing, causing pests to fall into a bag, thereby achieving the purpose of killing adults and controlling damage;
On the other hand, it uses light sources and wavelengths/wavebands that avoid the habits of natural enemies, which can effectively protect natural enemies. In Hongxiangsu pear orchards, generally one insect-killing lamp is hung every 40 mu, with a hanging height of 4-5 m. The lamp is turned on at 6 pm every day and turned off at 6 am. Each lamp can be used continuously for more than 4 years.
II. Hanging sex pheromone lures to trap and kill pear fruit moth
Pear fruit moth is the most important pest of Hongxiangsu pear. If control is unsuccessful, it may cause total crop failure in the pear orchard. This pest occurs 4-5 generations per year, with overlapping generations, making control extremely difficult.
In order to accurately understand the occurrence and damage patterns of pear fruit moth in Hongxiangsu pear orchards, pear fruit moth sex pheromone lures were used for forecasting and control, achieving good control results and effectively protecting and utilizing natural enemies. This is a good measure for producing pollution-free fruit.
Method: Take a water basin with a diameter of 20 cm, use a thin wire slightly longer than the basin diameter to thread through one lure and place it horizontally at the center above the basin opening and fix it, so that the lower edge of the lure is level with the basin opening, to prevent the lure from being soaked when the basin fills with rainwater.
After preparation, hang the lure basin on the shaded side of the fruit tree to prevent direct sunlight on the lure. The hanging height should be about 1.5 m from the lure to the ground. After placing the basin, add clean water to it, with 0.2% laundry detergent added to the water. The amount of water added should leave a distance of 1-1.5 cm between the water surface and the lower edge of the lure. The placement density is 5-6 lures per mu. The placement time starts from the end of June, before pear fruit moth begins to damage pear fruit, and ends in mid-September.
III. Using the latest pollution-free chemical control
Using bionic pesticides to control pests. The pollution-free bionic pesticide 5% beta-cypermethrin fenoxycarb can effectively control the main pests damaging Hongxiangsu pear. 5% beta-cypermethrin fenoxycarb is a high-efficiency, low-toxicity, green, environmentally friendly product with no environmental pollution. It is the preferred pesticide for producing pollution-free food and green food, and its toxicity is even lower than table salt.
This pesticide is the latest bionic pesticide with an insect growth-regulating effect, affecting the molting process of insects. When acting on pests, it can kill the eggs, larvae, and adults of pear tree pests throughout the entire process. Spraying 3-4 times per year at a concentration of 1500 times dilution can effectively control multiple pests such as pear psylla, Kang's mealybug, fruit borers, and aphids, while being safe for natural enemies.