Milk spray works against fungal infections on plants because of the lactobacillus and other types of cultures in it. Dunno about pasteurised milk, but adding some yogurt to the milky make the spray out of would probably ensure or increase its efficacy. I once used just "micro filtered" milk mixed with water and it worked. For the cypress tree disease in Italy, Neem oil (be sure to get the one made for mixing with water) mixed with Marseille soap, sprayed with a big agricultural sprayer, on the tree, and the trunk and on the ground around the tree, when the temperatures won't rise above 30 degrees centigrade, used with magnesium sulphate (Epsom salts)--a few heaping soup spoonsful scattered on the ground around each tree twice a year, or a stronger magnesium solution poured on the ground if the tree is really pale and wan, along with watering weakest trees in periods of drought helps. It is important to also prune allthe dead branches out and to take off any damage at the tip of the tree. The trees can grow back if there is even one good branch left, it will form a new tree. You need to spray in the weather which puts them most at risk, hot humid weather when it rains in the summer--it is tricky to time it properly. Be sure not to plant anything against the trunk that would hold water on the trunk, as it can cause the trunk to rot and kill the tree. I have the idea of trying using the natural mineral fertiliser fulvic acid around the trees at the beginning of summer. The magnesium sulphate makes the trees visibly greener. Neem oil seems to be more than a fungicide and insecticide, it seems to nourish the trees too. Another possibility for the fungal diseases is Effective Microorganisms (EM). The magnesium sulphate furnishes the central mineral that they need to use to make chlorophyl which should help them fight the disease by raising their metabolism. These things should help combat fungal disease on roses too.

Clio, Did the problem begin when the cold snap happened in your area? Maybe it was just a little too chilly for their tastes. If they are gathered close on your balcony and a fungal problem began, it will spread more quickly when they're close together. I lived for a long time in the Sonoma County area, and Pelargoniums tolerate the chilly nights there and seemingly endless winter rain with little problem. Maybe your plants believed they would always be warm and cozy in LA, and are mad about this winter's nasty weather. You folks really got nailed! Be sure to remove any sign of the fungal problem as soon as you see it, including any foliage that falls onto the soil of the pots & anything with new spots (because they might shed spores). If you can, maybe changing the spray time to early morning would help. Try to move them farther apart for a while, too. Hope this helps.

How marigolds are pest unfriendly Marigolds’ greatest claim to pest control fame is their effect, documented in numerous studies, on nematodes, which are a kind of worm that in some cases is destructive to plants. Featured Video A Sikh man dresses as a superhero to challenge what it means to be American (3:41) Most Read Life Stories Food & Wine declares Washington state's best barbecue spot They don’t own homes. They don’t have kids. Why millennials are plant addicts U.S. News & World Report ranks Alaska Airlines’ Mileage Plan as the nation’s best airline rewards program In a rapidly growing state, La Conner's pace of change is just right VIEW Cult-favorite bakery Milk Bar is coming to Seattle — for a day Like other members of the daisy family, marigolds also do their share in feeding nectar to beneficial insects, such as syrphid flies, who prey on aphids and other insects that attack garden plants. Members of the daisy family do not yield nearly as much nectar as flowers of the parsley family — dill, for instance — but daisy family flowers keep the nectar flowing longer. Other beneficial effects of marigolds are less dramatic or useful. They have been shown to have some slight effect in repelling cabbage worms from cabbage and their kin. And some marigolds, especially a variety called Stinking Roger, repel flies, except that the flies are the kind that bother cows and other domestic animals, not plants. Read and listen to claims made for marigolds, and you also could press it into service as a fungus killer, an insect killer, even a selective weed killer. Weigh pros and cons Hold on a second, however, before you blanket your garden in marigolds. Some of these claims have been blown out of proportion. Those marigolds that helped repel cabbage worms: They also stole water and nutrients from nearby cabbages. So which is better? Stunted cabbages, or those with some leaves lacy from caterpillar feeding? Marigolds, especially the Gem varieties, also are a favorite food of slimy slugs and Japanese beetles. As such, they have been used to stop Japanese beetle damage — by attracting the beetles away from other garden plants. Of course, such schemes commonly backfire by attracting more pests to the area than would have been there otherwise. And now, for some marigold reality If you really want their pest-controlling benefits, blanket your garden with oodles of marigolds. British studies showed that African marigolds killed weeds such as ground ivy and bindweed, but the marigolds were planted densely and early in the season, then allowed to grow 5 feet tall. Might not any tall, dense growth do the same? Similarly, marigolds suppress nematodes only when the marigolds are grown as a cover crop, that is, planted thickly and allowed to grow for many weeks. To sum up, marigolds seem to have little actual benefit in suppressing disease and above ground insect pests, except perhaps to woo certain insects away from other plants. Be wary of such claims as, “I planted marigolds in my bean patch and did not have any beetles to speak of, while my neighbor’s bean plants were devoured by Mexican bean beetles.” Was this gardener growing the same bean variety as the neighbor? Were soil conditions the same? Did he or she perhaps forget about the insecticide also applied? It happens. Below ground, marigolds do have some benefit — on nematodes, at least. However, you have to plant masses of marigolds to get this benefit and anyway, not every garden has nematode problems. So why are those marigolds in my vegetable beds? ‘Cause they look pretty. LEE REICH

No, the neem oil that is readily available in the US has no effect on bees unless you spray the bee with a smothering coat of oil. Raw neem oil has an insecticidal fraction called azadirachtin. Most of the oil is processed to remove the azadirachtin for separate sale (mainly to organic farmers, I suspect). The leftover oil is then marketed to naive gardeners. The label says "water extract of neem." It is just oil, probably no more effective than canola oil. However, any oil with smother small, soft-bodied insects if applied directly to them (a smothering coat). Neem that still has the azadirachtin in it is sold as "whole neem oil." You can probably find it online. You might also find an azadirachtin product somewhere. But the neem oil at typical garden centers has no insecticidal effect beyond just being an oil. Either Safer's soap or any oil can kill rose slugs if it coats their bodies. But spraying this thoroughly is as much trouble as squishing (as people say above). The recommended chemical insecticide is spinosad. It is relatively safe and easy on the beneficial insects. But I just squish.