Garden Sage: Olive harvesting, a relatively uncommon mushroom and black widow spiders

A: According to University of Arizona Cooperative Extension Plant Pathologist Barry Pryor it is Battarrea phalloides, known as the desert stalked puffball. Although it is relatively uncommon, it is seen yearly in various places.

In the U.S. it may be found in the Southwestern states and Hawaii. Its habitat includes dry sandy soils and it is associated with certain plants including Opuntia species such as prickly pear cacti. It is inedible and can grow to 15 inches in height.

Q: We have an olive tree loaded with olives in various stages of ripeness from partially green to fully ripe and falling from the tree. Is it too early to harvest and cure the olives?

A: Now is the right time to harvest and either brine them or press them for oil. Harvest is often timed when they start to change color from green to purple and it looks like yours are doing just that. The only difference between green olives and black olives is ripeness. Unripe olives are green and fully ripe olives are black.

Olives are cured or pickled before consumption, using various methods including oil-cured, water-cured, brine-cured, dry-cured, and lye-cured. Green olives must be soaked in a lye solution before brining, whereas ripe black olives can proceed straight to brining.

Arizona’s desert climate encourages rapid growth and olive trees grown for oil require less water than those grown for canning, so there’s a natural bond with the desert environment for olive oil production. Arizona grown-olives are produced primarily for their high quality oil.

Q: My question is about black widow spiders. We have been told that they are difficult to get rid of and we have had several on the outside of our home. Their web is different from most spiders so even if I see a black spider and the web is similar I kill it without checking for the red hourglass. I’m quite concerned for my grandchildren when they are here visiting, and my husband who loves to garden. First off are there black spiders that are look-alikes and should I also threat them with the same caution? What is the best way to get rid of them along with the eggs they lay? We have the outside perimeter of the house sprayed twice a year and the line of death has worked for the insects we don’t want in the house. However, walking into a spider web of any kind has me really uneasy.

A: The western black widow spider (Lactrodectus hesperus) is fairly unique in its coloration for our area so there are no lookalikes to be seen. There is a false black widow that is not venomous but it is found in southern California and other pacific coast states, primarily in urban areas as a house spider. Their color is more purplish-brown with pale yellow markings. The body of the black widow female is shiny and black and the hourglass mark on the underside is red.

The good news about black widows is that they are not aggressive and not seeking to bite humans. You are correct about them being hard to eradicate so part of being safe is teaching your grandchildren what they look like and to avoid handling them. Wearing gloves while working in the garden is always a good idea to protect against accidental encounters with black widow spiders and other things.

Perimeter pesticide sprays are not a good way to manage insects and spiders because they won’t provide long-term control. These days many pesticides degrade fairly quickly in the environment so spraying twice a year for no specific reason is basically recreational pesticide use. It is better to spot treat where and when you see insect pests so you get the best bang for your buck and so you don’t unnecessarily kill off good bugs that could be helping you manage other pests.

Reducing clutter around your home is one of the easiest ways to minimize encounters with spiders and other arthropods. Outdoors this often means keeping weeds and other vegetation under control and reducing piles of anything such as firewood or moving piles to outlying areas.

Outdoor lighting will attract insects and the spiders that eat them so you have to balance the safety of having lighting with keeping the lights from shining directly on structures. Because they are nocturnal you can hunt for spiders at night and dispatch them with your shoe or whatever tool you prefer. You can also remove them to an area away from your home if you want to be nice to them. After all, they are eating insects that might otherwise bother you so they’re not all bad.

Q: My prickly pear appears to be turning black in places. Also, the saguaro and the tree next to it seem to have a brown substance on the base. Are these termites? If so, how do you treat or is it too late?

A: Your prickly pear appears to be suffering from Phyllosticta pad spot, a fungal disease commonly seen in our area. It is spread by wind and rain so it travels easily from plant to plant. You can remove infested pads and plants if you like.

There is no way to prevent it from happening so managing the plant by pruning is really the only option. The saguaro may have termites; it is hard to see from the photo. Typically desert encruster termites (Gnathamitermes perplexus) will colonize the outside of older saguaros where there are dead woody areas. They bring their mud habitat with them so you might see what looks like mud caked on the base of the cactus. Scrape a bit off and you might see the small white termites run for cover. Since termites are only after the dead wood, the live part of the cactus is safe from harm.