In the process of rice cultivation, "dry heart" is a common issue caused by diseases or pests. Accurately identifying the causes of this condition and taking timely, targeted measures for prevention and control are essential to ensure high yields and stable rice production.
First, a basic method for diagnosing "dry heart" in rice:
(1) Dry heart caused by insect pests: Different pests cause similar symptoms, but there are key differences to distinguish them.
1. **Big cockroach**: These pests create large holes in the rice stems and leave a lot of feces between the sheaths and stems. The affected rice leaves, stems, and sheaths turn yellow. This damage is more severe at the edges of the field and less in the center.
2. **Stem borers (e.g., rice leaf folder)**: After hatching, young larvae feed inside the leaf sheath, causing water-soaked spots on the outer layer. These spots gradually turn yellow and die. As the larvae grow, they move into the stem, causing the flag leaf tip to yellow and, in severe cases, the entire heart to die. There are visible holes in the stems, with fewer insects outside the hole and more inside.
3. **Sanhua wolfberry (rice stem borer)**: Larvae first feed on the rice heart, causing dehydration and curling of the leaves. This is often called "false dry heart." If the infestation continues, the growing point is damaged, leading to complete death of the leaves and a true "dry heart." Japonica rice stems show smaller holes with no external feces, but white granular feces can be found inside.
4. **Cricket (locust)**: These pests cut off rice stalks from the base, causing yellowing and eventual death of the leaves. Affected plants are easy to pull up, with no holes or feces on the stems. This type of dry heart usually occurs when the field is dry or when there's prolonged drought.
(b) Dry heart caused by disease: Two major diseases—viral infection and bacterial blight—can also lead to dry heart.
1. **Viral disease**: Symptoms resemble those of Sanhua wolfberry, but there are no holes or feces on the stems. The heart leaves are hard to pull out, and when squeezed under a glass slide, they exude a sticky, milky substance.
2. **Bacterial blight**: This typically occurs during the tillering stage. Infected plants show curled, blue-dried leaves that eventually die. A small piece of diseased leaf, when pressed on a slide, releases a cloudy, slimy liquid.
Second, effective prevention and control measures:
1. For dry heart caused by locusts, use insecticides such as "Ruijinte," "Special Killing Cricket," or "Bug Cull" to treat the affected areas.
2. For damage caused by earthworms, mix rice bran with "Trichlorfon" and apply it during the field stage to attract and kill the pests.
3. To prevent dry heart due to viral infections, soak seeds in "Strong Chlorine" before planting and control vector insects like planthoppers and leafhoppers.
4. For bacterial blight, ensure proper seed disinfection and spray "Shi Bao Ling" or "Ye Kuning" in the early stages to manage the disease effectively.
By understanding the causes and implementing the right strategies, farmers can significantly reduce the occurrence of dry heart and improve rice productivity.
Natural Food Colorants
what is natural food color?
Natural food coloring refers to pigments extracted or prepared from plants, animals, microorganisms or other natural sources for coloring food. These pigments are naturally produced due to biochemical reactions in living organisms and do not contain synthetic chemical components.
Natural food colors can be divided into the following categories according to their source:
1. Plant pigments: This is the most common source of natural food pigments, including pigments derived from a variety of fruits, vegetables, flowers, and plant roots. For example, red beets can provide red pigments, carrots can provide orange pigments, turmeric can provide yellow pigments, and blueberries and purple potatoes can provide purple and blue pigments.
2. Animal pigments: These pigments are rare and usually come from the tissues or excretions of certain animals. For example, cochineal is a red pigment derived from the cochineal insects that live on certain cacti.
3. Microbial pigments: Some microorganisms, such as monascus, can produce specific pigments, such as monascus red pigments.
4. Mineral pigments: Although less used, certain inorganic minerals can also be used as natural food pigments, such as titanium dioxide (white) and iron oxide (red, yellow and black). However, due to possible toxicity issues with some mineral pigments, their use is often severely restricted or banned.
Natural food colors are generally considered safer and healthier than synthetic colors due to their nature. However, their color stability, heat resistance, light resistance, and interaction with other food ingredients may not be as good as synthetic pigments, so their application in the food industry sometimes presents some challenges. At the same time, the extraction and processing of natural pigments can also affect their cost and sustainability. Nevertheless, as consumer concerns about food safety and health increase, the demand for natural food coloring is growing.
Natural Food Colorants,Natural Food Pigments, natural food color
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