Insects harmful to the good development of plants have their most active season in summer; when autumn arrives their reproduction decreases and they are less problematic, although they do not disappear.
For this reason, you should continue to control the presence of aphids (especially during the first part of the season and if the plants continue to flower), as well as the white fly, the red spider and the mealybugs which, although to a lesser degree, will continue to act throughout the year because these insects find their ideal conditions in dry and hot environments, common in the interior of houses even if we are in the middle of winter, due to the heating.
In autumn many plants suffer from fungal diseases due to excessive watering which saturates the compost and causes root and stem decomposition.
A typical autumn disease is botrytis, which manifests itself with the appearance of greyish and soft buds, caused by the permanence in the plant of dead flowers and leaves.
Too moist environment or water retention in the foliage also produces fungal spots on the leaves. To treat these diseases use specific fungicide products, and to prevent them, it is essential that you remove the dead leaves and flowers and water them properly.
During the autumn months you should take special care to remove the flowers and wilted leaves. During this time, most plants show signs of exhaustion and go through a delicate time when they are prone to fungal diseases, which develop on dead tissues and multiply rapidly. In addition to reducing watering, you should also control humidity in the atmosphere and spray plants only when they really need it, because water retained in the leaves can damage them.