Penicillium lilac ((thorn.) samson) is an endophytic fungus, an important natural enemy of some plant parasitic nematodes, which can parasitize eggs and can also infect larvae and females, which can significantly reduce the harm of plant nematode diseases such as root-knot nematodes, cyst nematodes, stem nematodes and so on.
1. Overview of penicillium lilac
The main feature of this genus is that the conidia stalk is bottle-shaped or nearly spherical (bottle stalk), rotated on the hyphal end or short branch, and the conidia are monospore chain-like, and so far there are nearly 50 species reported in this genus, all of which are insect pathogens and nematode pathogens. [1] This bacterium is widely distributed around the world, with the advantages of high efficacy, wide host, easy culture, etc., especially in the control of plant pathogen nematodes. For more than half a century, many experts and scholars at home and abroad have conducted extensive and in-depth research on this fungus, and have made a series of research achievements in biology, ecology, mass cultivation, pest control efficiency and field application.
2. Harm control effectiveness
On plant pathogen nematodes
Penicillium lilac is an effective parasitic bacterium for southern root-knot nematode and white cystic nematode eggs, and the egg parasitism rate of southern root-knot nematodes is as high as 60% to 70%. It has a control effect on a variety of nematodes, and its hosts are root knot nematodes, cystic nematodes, golden nematodes, ecdermal nematodes, and even human and animal intestinal roundworms, which is the most promising biocontrol preparation for the prevention and control of root knot nematodes.
The inhibition mechanism of Penicillium lilace on root-knot nematodes is that after penicillium lilac comes into contact with the nematode oocyst, in the viscous matrix, the biocontrovirus hyphae surround the entire egg, the hyphae end becomes thicker, the surface of the egg shell ruptures due to the activity of exogenous metabolites and fungal chitinase, and then the fungus invades and replaces it. It can also secrete toxins to play a toxic role in nematodes.
To insects
According to literature, penicillium lilac can parasitize litchi bugs and rice black bugs of the order Hemiptera; leafhoppers and brown planthoppers of the order Homoptera; termites of the order Isoptera; sweet potato weevils of the order Coleoptera, as well as tea silkworms and lamp moths of the order Lepidoptera.
On plant pathogens
Penicillium lilac 36-1 strain has antagonistic effects on plant pathogens. In the experiments of maize small spot disease, wheat gibberellosis, cucumber anthrax, cotton blight and rice malignant seedling disease, the inhibition rates of hyphae growth of live bacteria of Penicillium lilac strains were 80.22%, 80.50%, 77.71%, 75.30% and 61.36%, respectively, and the inhibition rate of green and green mold expansion was 65.97% in citrus fruit surfaces. The batch treatment of citrus, the good fruit rate was 78.44%, which was 54.44% higher than that of the control.
3. Physiological effect of secondary metabolites of Penicillium lilac
Promotes plant growth
In the culture process of Penicillium, especially in the process of special medium and deep fermentation culture, the bacteria can produce rich derivatives, one of which is similar to indole acetic acid product, its most significant physiological effect is to promote the growth of plant roots and plants at low concentrations, so the application of bacteria in the plant root system can not only significantly inhibit nematode infestation, but also promote the growth of plant vegetative organs, while also promoting the germination and growth of seeds.
Produces a variety of functional enzymes
This bacterium can produce rich chitinase, chitinase has a degrading effect on chitinase, it can promote the hatching of nematode eggs, improve the parasitic rate of penicillium on nematodes, in addition to producing cell lyase, dextranase and silk protease, galvez-mariscal studies have shown that protease and dextranase, amylase activity in highly efficient strains is 1.2 to 4.2 times and 20 to 120 times higher, these enzymes promote cell division.
Degradation effect
Somaseknar study found that penicillium lilac can promote the dissolution of insoluble phosphate, laboratory studies confirmed: penicillium solubilization effect of 30%, other nematode antagonism antibacterial reached 20% to 40%. Similar studies have also shown that penicillium can also promote the decomposition of many chemical polymers (such as pesticides, tanning wastewater, etc.), which proves that penicillium lilac has a certain environmental effect.
4. Penicillium lilac
Penicillium lilac is a pure microbial live spore preparation, which has the characteristics of high efficiency, spectroscopy, long-term effect, safety, no pollution, no residue, etc., which can significantly stimulate crop growth. The test proves that the application of lilac penicillium agent around the plant root system can not only significantly inhibit the infestation of nematodes, but also promote the growth of plant roots and plant vegetative organs, such as seed mixing before sowing, application at the time of colonization, which has a promoting effect on the germination of seeds and the growth of seedlings, and can achieve seedling full, green seedlings and strong seedlings, and generally increase crop yield by more than 15%.
5. Control of vegetable root knot nematodes
The main biological type of biological control of plant nematode disease in organic vegetable production, Penicillium lilac, proposes ways to improve the effect of biological control. Plant nematode disease occurs in China, the harm is serious, almost every crop has 1 to 2 kinds of nematode disease, some of the occurrence area continues to expand, the harm is getting more and more serious, has become one of the most urgent problems to be solved in agricultural production. Penicillium lilace application of penicillium lilac agent around the plant root system can not only significantly inhibit the infestation of nematodes, but also promote the growth of plant roots and plant vegetative organs.
Conventional chemical control pesticides are more toxic and endanger the production of green food, so new technologies should be sought. Penicillium lilac biopesticides biological control plant pathogen nematodes is a hot spot in the current research, and it has been found that organisms that can control nematode disease include fungi, nematodes, planarians, nematodes, nematodes, insects, mites, etc.; viruses, protozoa, bacteria, etc. of parasitic nematodes; Plant extracts can also be used, and its control effect is also better.
Biological control is the most promising control method for disease control at present, which is in line with the concept of environmental protection and health. However, there are very few biological control products used to prevent and control root-knot nematode disease in China, and most of the biocontrol preparations that have an effect on root-knot nematodes are still in the research and development stage. The only biocontinent products currently registered are "nematode bik" and avermectin, as well as the recently registered penicillium lilac. Avermectin is more used in the control of vegetable root-knot nematodes. 0.5% avermectin granules can be used to apply in the ditch or cave at 15-17.5 g/mu. However, as a biopesticide avermectin, there is an inevitable weakness of almost all biopesticides, that is, the effect of field use is not stable.
Root-knot nematode disease is mainly harmful to vegetable roots, and lateral and whisker roots are the most vulnerable. The affected roots produce tumors or root knots of varying sizes, which are initially white, soft, and later become light yellowish brown or dark brown, with a rough surface and sometimes cracked. When the root knot is cut open, small white pearl-like particles can be seen, which are female adults of root knot nematodes. Vegetables grow slowly after being infected with root-knot nematodes, and the leaves are small and yellow. When the disease is severe, the plant is short, not fruitful or poorly fruited, and in high temperature and drought weather, the plant is prone to wilting or even dying.
6. Active ingredient (live penicillium lilac spores)
Toxicity: Acute oral rats ld50 is greater than 5400mg/kg, acute inhaled rats lc50 is greater than 2300mg/m3, acute percutaneous rats ld50 is greater than 2350 mg/kg, no irritation to the eyes and skin, mild sensitization, low toxicity to fish and birds, safe for bees and silkworms.
Mechanism of action: After the germination of lilac cyanobacteria spores, the hyphae produced can penetrate the egg shell, larval and female adult body wall of nematodes, and the hyphae absorb nutrients in their bodies, reproduce, and destroy the normal physiological metabolism of eggs, larvae and female adults, resulting in the death of plant parasitic nematodes.
Control objects: soybeans, tomatoes, tobacco, cucumbers, watermelons, eggplant, ginger and other crops root knot nematodes, cystic nematodes.
7, How to use
1. After seeding is mixed according to 1% of the seed amount, it can be sown after being piled up for 2-3 hours and dried in the shade.
2. Treat the seedbed and mix the lilac penicillium agent with the appropriate amount of substrate and sprinkle it into the seedbed and sow the soil. 1 kg of fungal agent to treat 30-40 square seedbed.
3. Treat the nursery substrate and mix 1 kg of fungus evenly into 2-3 square substrates and load them into seedling containers.
4. Apply the hole near the root system of the seed or seedling, and the amount per mu is 0.5-1 kg.
Notes:
1. Do not mix with chemical fungicides.
2, please pay attention to safe use, penicillium lilac can parasitize the cornea, if you accidentally enter the eye, please rinse immediately with plenty of water.
3. The best time to apply the drug is in the morning or evening. Do not place the agent directly in strong sunlight.
4. Store in a cool and dry place, do not let the agent get wet.
