Linnea, the most common method used to treat oyster shell scale insect is with rubbing alcohol which is applied in different ways. One is to use a Q-Tip, soaked in the alcohol and the bug is then touched. The alcohol eats through the hard shell and kills the bug. Each bug though must be touched to be effective. The other method is to treat the plant. In a quart spray bottle, put 20 oz water, one tablespoon of dishSOAP and 4 oz rubbing alcohol. This amounts to about a 2% solution. If you feel it might be too strong, double the amount of water/half the amount of the other. Take the plant out where you can spray indiscriminately and spray from top to bottom, bottom to top, ensuring all parts are covered. Wait ten minutes, then rinse wellw ith tepid water. Again, from top to bottom, bottom to top and let's not forget to treat the soil as well. That's where the children are. This method must be repeated 3 times in 20 days to break the cycle of the bug from egg, to larvae, to adult. Then constant vigil is needed. Another method is to use the dormant oil that is used outside in combo with lime sulfur. Most plant bugs can be treated with the soap and water without concern of damage as long as the soap is not left on the plant. Most bugs can be treated initially by simply hitting them with a stream of water.

ants and wasps ... as noted.. milk honeydew from the scale .... they are not the problem.. they are a response to a problem ... remove the problem.. and they will go onto other things ... scale is extremely hard to get rid of ... dormant oil is one solution... the other would be systemic chemicals ... like bayer tree and shrub ... it may take years of treatment... to cure the plant... i tend to agree with jean.. i would apply a saw at or above ground level.. and then dig up the roots and send it to the landfill or burn it ... the cost of replacement is NOT worth the exposure to the chemicals ... good luck ken

Adult scale particularly pink scale are almost impossible to kill because their waxy coating prevents the white oil from penetrating. What you have to do is break the breeding cycle by spraying every 2-3 weeks to kill the emerging baby scale insects before they form the protective wax coating. The adult scale dies once it has bred and sporned its young so it is the young scale you target ie 2-3 weeks and after there are no signs of more young you keep spraying for at least another 3 week cycle to ensure you have got them all. One surviving scale insect will re-infest the plant. At the same time as spraying for scale kill the ants present as it is the ants which farm the scale for the sticky secretion exuded by the scale. Black sooty mold is another sign of scale as it is the secretion that causes sooty mold. The white oil will also kill the mold. A good alternative to control sooty mold is a tablespoon of LUX laundry flakes dissolved in half a bucket of hot water and then diluted down to make 20 litres of spray. Don't use more flakes than stated, it is unnecessary besides too much soap on your plants is not good for them. Lux beats detergent and cooking oil mixtures hands down and it will also control SOME of the soft scales and you don't need a space suit to spray it. If you use a lot of white oil try your local Ampol/Caltex bulk fuel depot for "Ampol DC-Tron Plus". A 20 litre drum here in Brisbane is about $80. DC Tron Plus is the same product as one of the major fertiliser suppliers sold in nurseries for about $15 for 500ml. The nursery branded product is bought from Ampol and repackaged under their own brand. Doug. Doug.

Scale is one of those insect pests that really should be treated. They can seriously weaken a tree and they easily migrate to other plants. If it is a hard shelled scale, spraying with dormant oil won't have much of an impact - that shelled surface makes them pretty much impervious to the spray. It is best to treat these when they are in a far more vulnerable instar stage. And to know when that is, you need to identify the kind of scale - there are dozens. Check to see if these have a hard shell and then post clear, close up photos for an ID. If a soft bodied scale, the dormant oil should work well.