How to grow Brassavola orchids? Detailed guide to cultivation methods and key points
Brassavola orchids are native to South America and have an incredible fragrance. Moreover, these pure white, ghostly flowers only release their intense fragrance at night. The flowers bloom multiple times a year, and the flowering period is long. Let's take a look at the key points for growing them.
Branch
Brassavola orchids belong to the Laeliinae branch. There are about 17 species of Brassavola; they are native to the tropical regions of the Americas. The standard and most common Brassavola is Brassavola nodosa, which can be grown in baskets or in containers filled with orchid mix.
Brassavola orchids have long, thin, tubular leaves up to one foot long, which sometimes appear spread out or flattened. Brassavola orchids and their hybrids have much smaller pseudobulbs than other epiphytic orchids, so the leaves generally appear to arise directly from the rhizome without thick pseudobulbs. Typical Brassavola orchids have enlarged, ladle-shaped lips, with petals and sepals reduced to spear-shaped segments. Brassavola orchids are white to attract moth pollinators, but the plant has been extensively hybridized to create flowers in many colors.
Light
Even in direct sunlight, the light for Brassavola orchids is quite intense and bright. Healthy Brassavola orchids have mottled leaves with slight reddish markings on the leaves. Dark green leaves usually indicate that the plant is not receiving enough light, so the plant should be moved to a brighter location.
Water
The tubular leaves on Brassavola orchids are designed to reduce water evaporation, making them more drought-tolerant than many other orchids. Therefore, the plants require less humidity and water than many other epiphytic orchids. During the growth cycle, they can be watered once a week, while potted Brassavola orchids should be watered thoroughly every week. Drooping or wrinkled leaves indicate water stress, and the plant should be watered as soon as possible.
Fertilizer
Brassavola orchids produce several red leaves throughout the year, and healthy plants are lantern grass all year round. Therefore, the plants should be fed year-round with a weak fertilizer solution (1/4 strength weekly). Many growers make "fertilizer balls" using nylon hosiery and controlled-release pellets, then place the balls on the plants, thereby providing a small amount of fertilizer each time the plant is watered. Nylon fertilizer balls will last for several months.
Temperature
Brassavola orchids prefer intermediate temperatures and will bloom better in warm conditions.
The fragrance released by Brassavola on summer nights is so wonderful.
Flowering
Brassavola orchids are moth-pollinated, so the flowers on Brassavola are pale to attract pollinators. Brassavola orchids bloom year-round, with multiple flowers and flower spikes with each flush. Ball-shaped clusters of flowers are often seen throughout the year.
Brassavola cultivation is fairly easy, and it can adapt to the basic conditions for epiphytic orchids. Humidity maintained at 75-80% is ideal, and sunlight can be relatively more abundant, while the temperature must be above 10 degrees. The graceful B. cucullata plant has a drooping habit, needle-like leaves, large single flowers, a longer flowering period, and fragrance.
Cultivation methods for Astragalus dahuricus
For planting Astragalus dahuricus, select mountainous or semi-mountainous areas with a sunny aspect, deep soil layers, and fertile sandy loam or brown forest soil. For flat land, select sandy loam or accumulated soil with higher terrain, strong permeability, and a low groundwater table. Avoid albic soil, saline-alkali soil, clay loam, and waterlogged meadow soil.
When planting Astragalus dahuricus, the soil should be deeply plowed and barnyard manure or compost should be applied at 2500 kg per mu, along with 25-30 kg of superphosphate. After fine cultivation, make beds 120 cm wide and 30 cm high.
Manual weeding is the same as for field crops. Herbicides can also be used, namely trifluralin at 150 g per mu applied at or after sowing, or alachlor at 200 g per mu.
In early May, topdress with ammonium sulfate at 5-15 kg per mu; in early June, topdress with urea at 7-10 kg per mu; in early July, topdress with superphosphate at 50 kg per mu and barnyard manure at 2000 kg.
For the management of seed fields, on the basis of general field management (do not remove the flower buds), apply an additional phosphorus and potassium fertilizer in mid-July, with 25 kg of superphosphate and 10 kg of potassium chloride per mu, to promote abundant flowers and fruit and plump seeds. During the period when the fruits set and the seeds ripen, if high temperature and drought occur, irrigation should be carried out in time to reduce the hard-seed rate and improve seed quality. Astragalus seeds should be harvested in August, immediately when the pods droop, turn yellow and ripe, and the seeds turn brown; otherwise the pods will split open, the seeds will be lost, and harvesting will be difficult. Because the seed maturation period is uneven, harvest as they ripen. If saving seed on a small area, it is best to harvest in stages and batches, cutting off each mature ear one by one, discarding the immature fruits at the tip of the ear, and keeping the mature pods in the middle and lower parts. If saving seed on a large area, harvest all at once when 70-80% of the fruits in the field are mature. After harvesting, first hang the fruiting branches upside down in the shade to dry for a few days so the seeds after-ripen, then sun-dry, thresh, winnow clean, and store.
Different types of cornfield herbicides and how to choose and use them
Methods for using cornfield herbicides. The main weeds in cornfields include crabgrass, redroot pigweed, yellow foxtail, Chloris virgata, lovegrass, black nightshade, barnyardgrass, Amaranthus hypochondriacus, small goosefoot, Chenopodium glaucum, purslane, emarginate amaranth, Russian thistle, Kochia scoparia, prickly amaranth, green foxtail, Amaranthus paniculatus, amaranth, goosefoot, green amaranth, goosegrass, Celosia argentea, Chenopodium aristatum, Acalypha australis, Abutilon theophrasti, wild watermelon seedling, Amaranthus axillaris and other weeds. Perennial weeds include bindweed, reed, and purple nutsedge. Let's take a look below at the methods for using cornfield herbicides!
Pre-emergence herbicides after sowing
1. 40% acetochlor-atrazine aqueous suspension concentrate (acetochlor-atrazine mixture)
40% acetochlor-atrazine aqueous suspension concentrate is a special-effect herbicide for cornfields. It has excellent control effects on annual grass weeds in cornfields such as crabgrass, green foxtail, barnyardgrass, goosegrass, Leptochloa chinensis, lovegrass, and bluegrass, and on annual broadleaf weeds such as goosefoot, knotweed, amaranth, black nightshade, cocklebur, eclipta, purslane, Acalypha australis, chickweed, Polygonum aviculare, Kochia scoparia, Carduus crispus, Conyza canadensis, and dayflower. It also has a noticeable inhibitory effect on sedge weeds.
40% acetochlor-atrazine aqueous suspension concentrate not only has a broad weed control spectrum, but also has high herbicidal activity and a long period of use. It is very safe for corn and subsequent crops such as wheat. From after corn sowing and before emergence to before the 3-leaf stage of weeds after corn emergence, apply 40% acetochlor-atrazine aqueous suspension emulsion per hectare: 2250-3000 g for summer corn in North China, 2250-3750 g for spring corn in North China, and 4500-6000 g for spring corn in Northeast China, adding about 750 L of water, and spray evenly. The field residual effect period is 50-60 days, and one application can ensure that corn is free from weed damage throughout the entire growth period.
The herbicidal effect of acetochlor-atrazine aqueous suspension emulsion is closely related to soil moisture. When moisture is relatively high, the efficacy is good; when the soil is dry, the efficacy is low. Usually, before application, it is necessary to irrigate once, either lightly or heavily, or there should be rainfall. The timing of application must be strictly controlled. It is best to apply before weeds emerge to ensure the efficacy is fully exerted. If applying after emergence, it is also best before the 3-leaf stage of weeds. After the 4-leaf stage, if the weeds are too old before application, the efficacy will decrease because the weeds' resistance increases. When using this agent on sandy loam soil with low organic matter content, the dosage should be appropriately reduced.
2. Acetochlor-bensulfuron tank mix
Acetochlor-bensulfuron tank mix is a ready-to-mix tank mixture made from acetochlor and bensulfuron. It can be used in cornfields and corn-soybean intercropping fields to effectively control annual grass weeds and annual and some perennial broadleaf weeds. The field residual effect period is 30-60 days, and it is very safe for corn, soybean, and subsequent crops such as wheat. Apply before crop sowing or after sowing and before emergence. In spring cornfields in Northeast China, use 3000 mL of 50% acetochlor plus 26.7 g of 75% bensulfuron per hectare; in summer corn (or intercropped soybean) fields, use 1500 mL of 50% acetochlor plus 19.95 g of 75% bensulfuron per hectare, with 450-750 L of water, and spray evenly. When mixing the pesticide, first dissolve bensulfuron in a small cup with a small amount of warm water to make a stock solution, pour it into a mixing tank already containing half the water, then add acetochlor, then add the other half of the water and stir evenly. Application with a fan nozzle gives the best effect.
3. 50% Hewei emulsifiable concentrate
50% Hewei emulsifiable concentrate is a new type of herbicide that is efficient, broad-spectrum, and safe. It can effectively control many annual grass weeds and broadleaf weeds. It is most effective against crabgrass, barnyardgrass, goosegrass, green foxtail, large lovegrass, Leptochloa chinensis, Chloris virgata, Polygonum lapathifolium, small goosefoot, Chenopodium glaucum, redroot pigweed, prickly amaranth, emarginate amaranth, purslane, Acalypha australis, eclipta, and black nightshade. It also has a noticeable inhibitory effect on some perennial weeds and Cyperaceae weeds.
50% Hewei emulsifiable concentrate can be used both for post-sowing pre-emergence soil sealing treatment and for stem treatment after corn emergence before the 3-leaf stage of weeds. Apply 1.2-1.5 L of 50% Hewei emulsifiable concentrate per hectare, add 750 L of water, and spray evenly, which can effectively control various weeds. Soil moisture is closely related to efficacy; when moisture is suitable and soil moisture conditions are good, efficacy is high. This pesticide is sensitive to weed seedlings, so application after corn sowing and before emergence or in the early post-emergence stage gives the best effect.
4. 50% Du-A mixture
After corn sowing and before emergence, apply 2-35 kg of 50% Du-A mixture per hectare, add 750 L of water, and spray evenly on the soil surface. It has good control effects on annual grass weeds and annual broadleaf weeds such as crabgrass, goosegrass, green foxtail, lovegrass, goosefoot, emarginate amaranth, redroot pigweed, Polygonum aviculare, eclipta, cocklebur, purslane, black nightshade, and velvetleaf.
5. Atrazine
Atrazine is a triazine selective pre-emergence and post-emergence herbicide. It can be used to control annual monocotyledonous and dicotyledonous weeds such as crabgrass, green foxtail, lovegrass, goosegrass, shepherd's purse, eclipta, cocklebur, purslane, black nightshade, Euphorbia humifusa, Cirsium setosum, and species in the Lamiaceae and Fabaceae families. It also has a certain inhibitory effect on some deep-rooted weeds.
After corn sowing and before emergence, apply 2.25-2.7 kg of 38% atrazine suspension concentrate per hectare. During the corn seedling stage, before the 3-leaf stage of weeds, apply 2-2.25 kg of 38% atrazine per hectare, add 750 L of water, and spray evenly.
Atrazine has good efficacy, has good selectivity for corn, and is very safe, but its field residual effect period is as long as 120-160 days. If used improperly, it can easily cause phytotoxicity to subsequent crops. The dosage must be strictly controlled, the amount must not be increased arbitrarily, and attention should be paid to even application to avoid repeated spraying and missed spraying. Atrazine can be mixed at reduced rates with acetochlor, metolachlor, alachlor, and cyanazine, which both broadens the weed control spectrum and reduces soil residues, making it safe for subsequent wheat.
6. Acetochlor
Acetochlor is an amide selective pre-emergence herbicide. It has a special effect on annual grass weeds such as goosegrass, crabgrass, barnyardgrass, green foxtail, lovegrass, Leptochloa chinensis, bluegrass, and wild millet, and also has good control effects on broadleaf weeds such as goosefoot, knotweed, amaranth, and purslane. After corn absorbs acetochlor, it can be quickly degraded into non-toxic substances, so it is safe for corn. After corn sowing and before emergence, in Northeast China apply 2.25-3.75 kg of 50% acetochlor emulsifiable concentrate per hectare; in North China and areas to the south, apply 1.2-2.5 kg of 50% acetochlor emulsifiable concentrate per hectare, add 750 L of water, and spray evenly on the soil surface. For plastic-film mulched fields, reduce the dosage by about 1/3.
In areas with fertile soil and high organic matter content, the dosage needs to be increased; in areas with poor soil and low organic matter content, the dosage should be appropriately reduced. High soil moisture is conducive to the absorption of the herbicide by weed seeds, and the efficacy is good. Soil drought affects the exertion of efficacy. Therefore, before application it is best to irrigate or have rainfall so that the soil has good moisture conditions.
7. Metolachlor
Metolachlor is a selective pre-emergence soil treatment herbicide, and its effect on grass weeds is better than on broadleaf weeds. After corn sowing and before emergence, apply 1.2-1.8 kg of 72% metolachlor emulsifiable concentrate per hectare, add 750 L of water, and spray evenly. Use the low rate on sandy soil and the high rate on clay soil. If the soil surface is dry, it is best to shallowly incorporate it into the soil.
8. Alachlor
Alachlor is an amide selective pre-emergence herbicide. This pesticide has high herbicidal activity, with a residual period in soil of 4-8 weeks, and can effectively control annual grass weeds and some annual dicotyledonous weeds. After corn sowing and before emergence, apply 3-4.5 kg of 48% alachlor emulsifiable concentrate per hectare, add 750 L of water, and spray evenly. If rainfall or irrigation occurs within 1 week after application, it is conducive to the exertion of efficacy. Under dry conditions, after application, shallow soil incorporation should be carried out to a depth of 2-4 cm, which can improve the weed control effect.
9. Hennessy
Hennessy is an amide selective pre-emergence herbicide. Hennessy has a special effect on annual grass weeds such as barnyardgrass, green foxtail, Leptochloa chinensis, bluegrass, and Alopecurus aequalis, as well as on bitter cress, and also has a certain control effect on knotweed, goosefoot, amaranth, dayflower, black nightshade, purslane, and yellow nutsedge. It should be applied before weeds emerge; after weeds have sprouted and grown large, it cannot kill them. After corn sowing and before emergence, in North China apply 0.9-1.2 L of 90% Hennessy emulsifiable concentrate per hectare; in Northeast China 1.5-1.8 L; in the Yangtze River basin and South China 0.6-0.9 L; for plastic-film mulched corn 450-675 mL, add 600-900 L of water, and spray the soil surface. After application, a certain amount of soil moisture is needed to fully exert the efficacy. In dry areas or areas with low rainfall, pre-sowing soil treatment can be used: after application, shallowly incorporate into the soil 2-3 cm, then sow after incorporation.
10. Tank mixing of herbicides
Different herbicide varieties have different weed control spectra. Although some herbicide varieties have relatively broad weed control spectra, the spectrum is still limited due to crop safety constraints. Furthermore, some herbicides, because of high water solubility or too long a field residual period, excessive dosage, or uneven application, can easily cause residual phytotoxicity to the current crop or subsequent crops. Therefore, in production, two herbicides with different weed control spectra and complementary advantages are mixed at appropriately reduced rates. This not only broadens the weed control spectrum and significantly improves the weed control effect, but also avoids the possibility of phytotoxicity to the current crop and residual phytotoxicity to subsequent crops.
Post-emergence foliar spray herbicides
Abao tank mix is a one-time post-emergence herbicide for cornfields composed of atrazine and Baocheng. It can control various grass weeds and broadleaf weeds in cornfields such as barnyardgrass, crabgrass, goosegrass, green foxtail, wild oat, wild sorghum, goosefoot, amaranth, Rorippa palustris, dayflower, shepherd's purse, purslane, Russian thistle, beggarticks, wild watermelon seedling, ragweed, Ixeris denticulata, Galeopsis bifida, and Cirsium setosum. Its residual effect period is moderate, it is safe for the current crop and subsequent crops, and it can also achieve good weed control under dry conditions. Apply at the 3-5 leaf stage of corn. In summer cornfields in North China, use 1500 mL of 38% atrazine plus 60 g of 25% Baocheng per hectare; in spring cornfields in Northeast China, use 2250 mL of 38% atrazine plus 750 g of 25% Baocheng per hectare, add 450 L of water, and spray evenly. If 0.1%-0.2% nonionic surfactant or neutral laundry detergent is added to the spray liquid, the weed control effect can be improved.
After corn emergence at the 3-5 leaf stage, when monocotyledonous weeds are at the 1-2 leaf stage and dicotyledonous weeds are at the 2-4 leaf stage, per hectare you can use 3000-3750 mL of 40% acetochlor-atrazine aqueous suspension emulsion, or 1200-2500 mL of 4% nicosulfuron aqueous solution, or 3000 mL of 50% Du-A mixture, or 2250 mL of 38% atrazine suspension concentrate plus 1500 mL of 33% pendimethalin emulsifiable concentrate, or 2250 mL of 38% atrazine suspension concentrate plus 900 mL of 4% nicosulfuron aqueous solution, or 1800 mL of 38% atrazine suspension concentrate plus 300 mL of 48% dicamba aqueous solution, add 750 kg of water, and spray evenly. In cornfields with heavier broadleaf weed occurrence, at the 4-6 leaf stage of corn, per hectare use 15 g of 75% tribenuron-methyl (broadleaf net) dry suspension concentrate, or 15 g of 75% bensulfuron (broadleaf scatter), or 375-450 mL of 48% dicamba aqueous solution, or 750 mL of 72% 2,4-D butyl ester emulsifiable concentrate, or 750-900 mL of 20% bentazon emulsifiable concentrate, add 450 L of water, and spray evenly.
In some areas, if before or after corn sowing and emergence, due to labor shortages during the busy three-summer season, or because of hot and rainy weather, there is no time to apply herbicides for weed control, and weed outbreaks occur in the middle and late stages of corn growth, per hectare use 3 L of 20% paraquat aqueous solution, or 9-12 L of 10% glyphosate aqueous solution, or 3-4.5 L of 41% Roundup aqueous solution, add 450 L of water, add a shield to the nozzle, and spray directionally at the weeds, trying to avoid spraying the liquid onto corn stems and leaves.
No-till cornfield herbicides
The Yi-A-Le tank mix made from acetochlor-atrazine mixture and Nongminle is an ideal herbicide for no-till stubble-sown cornfields. This agent has a broad weed control spectrum and notable efficacy. It can both control all weeds that have already emerged and control or suppress annual grass and broadleaf weeds that have not emerged and reproduce by seed. It has a long residual effect period, and one application can ensure that the entire growing season is free from weed damage. Moreover, it is very safe for the current crop and subsequent crops. After wheat harvest and before corn sowing, use 2250-3000 g of 40% acetochlor-atrazine mixture plus 600-900 g of 74.7% Nongminle per hectare, with 450 L of water. The nozzle height should be 30 cm above the weeds, and spray evenly.
Plastic-film mulched cornfield herbicides
In spring corn areas with lower temperatures and drought, plastic-film mulching cultivation techniques are often used to increase soil temperature and preserve moisture, so as to promote rapid corn emergence and growth. Because the temperature under the plastic film is high, the temperature is very conducive to the exertion of herbicide efficacy. Therefore, compared with open-field application, lower herbicide dosages (generally reduced by 1/4-1/2 compared with conventional rates) can achieve very good weed control effects. Per hectare, you can use 1800-2250 mL of 40% acetochlor-atrazine aqueous suspension emulsion, or 750-1050 mL of 50% acetochlor emulsifiable concentrate, or 900-1200 mL of 72% metolachlor emulsifiable concentrate, 600-750 mL of 90% Hennessy emulsifiable concentrate, or 2250 mL of 48% alachlor emulsifiable concentrate, or 1500-2250 mL of 33% pendimethalin emulsifiable concentrate. After corn sowing and compacting, add 450-750 L of water, spray evenly, then cover with film and seal the soil.
If applying herbicide in bands along the seedling row, calculate the dosage according to the actual treated area.
Herbicides for wheat-intercropped cornfields
In North China, wheat and corn relay intercropping cultivation involves sowing corn on the ridges of wheat fields in mid-to-late May. After sowing and before emergence, calculate the dosage according to the corn sowing area (that is, the actual treated area), and spray the soil surface with water. After wheat harvest, rotary till to destroy stubble and remove residual weeds in the wheat field, then apply herbicide according to the wheat strip. When applying herbicide in wheat stubble strips, the dosage should also be calculated according to the actual spray area.
To improve labor efficiency, it is also possible not to apply herbicide when relay intercropping corn, and after wheat harvest (when corn has already emerged), shallowly till to destroy stubble, then apply throughout the field a soil-treatment herbicide safe for corn seedlings, such as 40% acetochlor-atrazine aqueous suspension concentrate, acetochlor-bensulfuron tank mix, and 50% Hewei emulsifiable concentrate.