Your plants are not getting enough water for two reasons. The first is that water volume and watering duration are not adequate. The second is that as you water salts in the water are added to the soil in addition to natural salts that are native to our desert soils. These salts, in part, are sodium, carbonates, calcium, chlorine and perhaps some heavy metals. To correct the problem start watering every other day for a half hour then check the water penetration depth using a soil probe or long screwdriver. If they go in an inch or two in the ground then you need to water. If it goes in a foot or two don't water. Once a month or so a deep watering is needed to leach out salts causing them to past the root zone. The drying of the leaf edges is cause by the plant taking up salts through the root system which are then conducted up to the leaves. The leaf cells pump" out water into the "saltier" intercellular spaces so that equilibrium is reached between salts within and without of the cell. This removal of water from leaf cells causes the drying that you see."

This disease, call blossom-end rot, is caused by a localized deficiency of calcium in the fruits. Calcium is required in large quantities by growing cells like those in the blossom-end. When this rapidly growing tissue is deprived of the calcium needed for growth, especially cell-wall construction, tissues break down resulting in blackened, dry sunken spots or areas on at the blossom-end of the fruit. Water stress usually creates this disorder because inconsistent watering will not allow the plant to translocate sufficient calcium. Also high levels of nitrogen can cause vigorous growth early in the season which with water stress can compound the problem. Blossom-end rot is also seen in chili and bell peppers and members of the squash and melon family.

You have sunburned fruit. It is to late to apply sun-tanning lotion! I have found that it is best to plant melons, pumpkins, and winter squash after the first of July. The reason is that normally we will have some cloud cover and rain while the really hot weather of May and June is subsiding. Soil temperatures are warm enough so that seeds germinate rapidly. If you plant just after the last spring frost the plants will grow normally. However, the fruits will be produced to early and become sunburned because of the heat and poor leave cover, which shades the fruit, during the month of June when compared to plants sown in July. We have a long enough growing season to mature these crops in September and October. Our normal first fall frost in Cochise County is in late October. Try planting melons, pumpkins, and winter squash now and you will have better results, I guarantee!

Preemergent herbicides are a class of weed killers that are applied to the soil before weeds emerge from the ground. The activity of these compounds usually kill germinating seedlings before they emerge from the soil. The new roots and/or shoots absorb some of the material and the plants die. The herbicides are applied to the soil and are usually incorporated into the soil by tillage or irrigation after application. This is necessary because environmental factors such as sunlight cause these products to degrade over time. With pesticides there are several names of each compound that must be understood to avoid confusion. For a single pesticide compound there are three classes of naming. The first is the long chemical name from which a good chemist can reconstruct the molecular structure. The second is the common name, which is registered and approved by the EPA, and is peculiar to that compound no matter who is manufacturer. This common name is analogous a scientific or Latin name of a plant. The third name is the trade name. This name is copyrighted by the seller, but the same chemical can have many trade names. Similar to common plant names. After patent rights expire on the compound anyone can manufacturer the chemical and give it any name they choose. All of this information is found on the label by law. For example a common preemergent herbicide has a chemical name of: 3,5-dintro-N4, N4-dipropylsulfanilamide. The common name is oryzalin. Some trade names are Surflan, (this is the name that the manufacturer uses), Monterey Weed Stopper, or Weed Blocker. The manufacturer sells this compound to others who package Surflan in smaller home use size containers and give their packaged material another name like Monterey Weed Stopper.

Surflan and several other preemergent herbicides are yellow to orange in color. This is because they were synthesized and discovered they had herbicidal activity by the dye industry. Surflan for example is bright orange. When it is being applied by city employees, for example, on median islands or in park landscapes people have become irritated thinking they were using "Agent Orange"! This is not the case. The two are not related. The best time to apply Surflan herbicide in the landscape is in the spring and/or again in the fall. Surflan persist from four to six months depending on environmental conditions. It works well over crushed granite or gravel that does not have plastic under it. Surflan can also be applied to lawns, flower beds (where flower seed is not planted) or transplanted through. Surflan must be watered in within 30 day or it is broken down by sunlight. Here in the high desert it is best to get it watered in with in the first week. With proper and timely application a "weed barrier" is formed and many grasses and broadleaf weeds will be controlled. As with all pesticides read the label and follow all instructions.

There are several insects that will bore into and make galleries under the bark. These insects however for the most part attack only weak growing or old trees. The trees are nearly 34 years old and fall into the weak and old tree category. Generally fruit trees if cared for will live for 25 to 35 years. There are some exceptions like pear and apricot trees. I would not spend a lot of time on these trees that naturally declining anyway, other than taking them out and replacing them. I would plant some new fruit trees if you want to harvest fruit over the next few years.