Problems, Pests and Diseases with Frangipani.
The biggest disease/problem with frangipani in Australia is rust, it usually strikes after christmas when we get the rainy periods and high temps. Although it can look very bad it has no real effect on the plants apart from being unsightly but eventually the leaves will die & drop off or you can remove them and place them in a plastic bag then bin them. The spores spread through the foliage and the ground as well, overhead watering is not recomended as it spreads the disease. Once it has invaded a plant it remains in the plants system, Bayleton was recomended because it is systemic and kills the actual disease but it is no longer on the market although there is a liquid version with a different name still available from The Frangipani Gardens in Qld. You can also use copper oxychloride or Mancozeb to spray on the leaves, this will kill the leaves surface effects only, start this before the rust pustules are evident(as soon as you see the spots developing) and continue every couple of weeks. This can deter it but it is an ongoing battle and effects frangipani world wide. I also remove the lower leaves on my plants as well as some of the thicker foliage so that there is good air circulation in and around the plant. Over head watering is also a way thios can spread so water them at the base of the plant.
UPDATE : Scorpio is a new product on the market that works well on rust but it is very expensive and not easy to find. Triforine is another product that is extremely good on rust, it can be sprayed on the leaves(both sides) in spring then again in summer and autumn, it can be found at most garden centres.
Black Tip/ Rot
This is another problem through out Australia, black tip(above left) attacks the growth tip during winter with very cold temperatures and rot attacks the main stems/branches of the plants. Black tip usually will stop just below the growth tip and once the sap is flowing again it will slowly push through the infested areas but rot will work its way through the whole plant if not caught soon enough. I have had 2 metre seedling decimated by it and ended up with a piece only 10 to 20 cm above the root ball, you can loose whole branches to it and it spreads down through the core of the plant as well as to the tips. Plants can be saved but you need to act quick and remove the infected area back to clean wood and seal it with wound paint, as yet I havent found a reliable spray to fight this problem. You also need to watch out for inflo's that do not drop off as they can start to rot and it then goes into the the plant, I always make sure that inflo's are removed when they stop flowering unless they are developing either seed pods or turning into a new branch. Leaf scars can also be attacked so watch for them turning black, you can also coat the tips and suspect branches with Envy(or similar) prior to the cold as this can reduce the problem.
These are also commom problems, scale is the little brown/black/pink dots on the stems/backs of leaves and downey mildew is the white spores on the stems as well, both these can be treated with either pest/white oil(recipe/how to make in link at bottom of page) and fungicides, wettable sulphur is also good for mildew/mould.
Mealy bugs attack the leaves and new inflo's, the leaves distort and you can see little white masses on the inflo and right up the centre of the underside of the leaf, when you touch it the web like mass sticks to your fingers. Mealy bugs feed on the sap and can cause problems for your frangipani, if you see them you can simply hose them off with high pressure from you garden hose or you can spray with white oil(recipe at bottom of page), neem oil or any of the other insecticidle oils/soaps designed for this. There are also chemical deterrents but I prefer to stick with the natural methods. In the pics above the mealy bugs have been sprayed with white oil.
This is the black/dark red spots on the leaves, it can be sprayed with copper oxychloride for control. It spreads with overhead watering and touching leaves so make sure you water the root area and space your plants accordingly.
Spider mites are another problem insect that develop when the frangipani are rather dry, they like heat and no moisture. They look like lots of tiny spots all over the leaves, leaves look slightly yellowish/white because of them. Again treatment is pyrethrum, insecticidal soaps or one of the oils(white/neem) sprayed on both sides of the leaves.
You know when you have thrips as they leave a sticky substance all over your leaves and draw ants to them. While thrips are good pollinators they can cause problems as they suck the sap from the leaves. Treatment is the same as for spider mites.
Fruit Spotting Bug
These are the ones that attack the tips leaving little holes on it, I use pyrethrum spray or the bug guns as they are non toxic although you can use stronger chemicals if you want to.
These usually only attack the young seedlings in hot houses, a spray of white oil or pyrethrum will soon get rid of them, I dont like using oils on young plants as it can also cause other problems.
These will attack the new leaves in spring as well as throughout the growing season, you can either catch & squash them or spray for them, again pyrethrum is a good natural knock down for them or you can use a systemic treatment. Natural deterants are becoming very popular as well as home made ones using chilli peppers and garlic.
Ants can cause major problems for frangipani, they can cause root problems and also start nesting in dry /rotten branches and cause more wood to die, ant dust or similar in a spray/water mix can control them. Also if you use mulch turn it regularly.
Rarely you can get borers/grubs inside your plants, you will see the tree starting to die back for no real reason that is obvious apart from possible sawdust mounds on the branches, the only way you can be certain is to cut off the offending branch and look inside it to see if it is hollow, this is where you will need a systemic insecticide to do any good or try to cut the borer/grub completely out of the tree. Once you have this problem any cuttings you take will usually not grow roots as well, it caused problems in the plumeria groves in Hawaii several years ago.
Another problem we face in warmer climates is sunburn, especially when the leaves have not developed, sunburn effects the leaves and the wood itself. When the wood is burnt it turns an orange colour and it can eventually split causing rot when water gets inside it. Unfortunately there is not a lot you can do to prevent this apart from using a shade cloth cover but you can slow it down by coating the wood with Envy(or similar), it provides a clear protective coating that can reduce the vulnerability of the wood and growth tips to both heat and cold.
Over summer when there are high temperatures there is always the possibility for flowers to get "bleeds". Some growers insist this is actually Frangipani Mosaic Virus(FMV) but in most cases it isnt. FMV infects the whole frangipani(flowers also distort & leaves get black markings on them and the plant performs badly & eventually dies) where as a bleed will only effect a few flowers & only after/during hot weather. I have sent samples of my flower bleeds(above left) to be tested and they have come back clear of all virus', I have also had seedlings flower and have bleeds(above on keyboard), FMV cannot be transferred through seeds so they were also clear. This will remain an ongoing disagreement between some growers but always be careful to clean any tools used on any frangipani that exhibits bleeds just in case, in fact all tools/knives should always be cleaned/sterilized between use on all plants.
Ocassionally when there is damage to a branch on a frangipani(in the pics above you can see where the sunburn damage started this) we can get aerial rooting taking place, it looks unsightly but does no damage to the tree itself although it can also be an indicator that the root system is not working properly or the plant is under nourished. To check just dig down around the roots and check to see if there is a problem with possible root rot or insect damage, if there is lift the plant and remove problem roots and replant it or alternatively remove the wood below the aerial rooting and re-plant with the aerial roots below the soil line. If there are many sections of aerial rooting you need to make a choice of either removing it completely or simply letting it go.
If frangipani are not watered regularly or get a soaking rain occasionally they can suffer deformed leaves(above left) as well as "pruning" in the branches/stems. If you see these things happening then you will know you must water them more regularly. Mineral deficiency is caused through the leeching/lack of certain elements in the soil/mix, it causes discoloured leaves(above right) and can be fixed with the application of an multi mineral/trace element additive available from nurseries/hardware stores.
Although this is not a problem some people do not realize that it is simply a variant in the growth of the frangipani, it can effect the foliage, flowers and branches, some collectors even try to replicate it in other varieties. There are a few varieties that actually repeat thos process throughout their growth, "The Great Wall" is one in particular that does so.
This is another possibility with frangipani, they can develop multiple branches on the one branch/stem. We had several plants do it at the farm in Ballina, we tried to find out what caused it but had no luck, again it is probably a variation in the plants genetics. I have taken cuttings from the ones showing multi-branching and the cuttings have also ended up doing the same as the parent tree(pics above, these were single stem cuttings from 2 plants in Australia I brought to Thailand in 2012, "Rorange" & "Thing").
Inflo's Turning into Branches
This also happens a bit as well, there are certain varieties that seem to do it more readily than others but again it is nothing to worry about. In the pics above you can see one just starting to turn into a branch and the other is a tree with all inflo's that have turned into branches. There are a few different varieties that actually do this a lot, Tropical Tangerine was one in particular I noticed did it and the one above right is Sawmongnon(3 inflo's turned into new branches, 1 still flowering) but there are many more.
Lichen sometimes grows on the trunk/branches of frangipani, it is not harmful and many people think it looks good. It is usually a white or grey in colour and can be small spots(pic 2) or covering large areas(pic 1). If you do not like it you can scrub it off with a stiff brush and water or even scrape it off but apart from the way it looks there is no harm from it at all.
These are the main difficulties you will have with frangipani in Australia & world wide, again there are things you can do to help prevent them. Always paint the end of a cut when made to seal over the wood, this will stop ants and even rot taking hold. Trim off excess leaves so that there is good air circulation around the plant, this slows down rust and mould. Keep weeds away from the base of the frangipani, this can help with rust as well. If you have mulch around your plant turn it regularly to stop ants from nesting in it. When you mow your lawns spread your clippings around the base of the plant(away from the trunk), this will keep the roots warm as it breaks down and this in turn keeps the sap flowing and slowing any rot/black tip, you can also move your plants out of open areas if they are in pots so that they are protected during winter. A healthy plant is harder to attack so always take care of them and do not have any open wounds on the plants, when removing leaves you should always cut the leaf stem as the short piece remaining will yellow and drop off in a few days leaving a sealed wound, pulling the whole leaf off leaves an open wound that can become infected.