Cooking and purifying the base. 3 Next, the gum base is cooked in kettles at 243 degrees Fahrenheit (116 degrees Celsius) until it has melted into a thick syrup. To purify it, workers pass it through screens and place it in a high speed centrifuge before refiltering it, this time through finer screens.
When tomato leaves curl due to viral infections, you'll usually see other symptoms. Tomato plant leaves are sensitive to some viral diseases that cause the leaves to curl. These viruses affect the plantâs appearance and also reduce fruit yield and quality. If the only symptom is curled leaves, your tomato plant might have a condition known as physiological leaf roll.
The damage may appear as tiny or large holes in the leaf, or as irregularly shaped leaves with jagged edges. If plant leaves are still growing when the insect feeds, the damage may later appear to have smooth edges around the feeding holes. Only insects cause these types of damage. Leaf curling, puckering or rolling The saliva of some sucking insects, especially aphids, may cause plant leaves to fold, curl or pucker. These insect symptoms can be confused with some plant diseases that cause similar symptoms.