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.
Even if you donât use herbicides in your garden, overspray and wind-blown droplets may find their way to your tomato plants. Leaf curl is one sign of herbicide damage. Depending on the herbicide, leaves may tilt down with curled edges to form cupped leaves, or the leaves may pucker and curl.
Symptoms: Leaf miner larvae tunnel through the lamina of the tomato leaf eating the chlorophyll-rich mesophyll cells as they go. This leaves an irregular track of dead tissue that eventually causes the leaf to stop functioning. High levels of damage on vegetable crops cause stunted growth and reduced yield. High populations of adult flies can injure leaves by producing egg-laying and feeding scars called âstipples.â