The sycamore plant bug feeds on the leaves of its host in all nymphal (immature) life stages as well as the adult. Sycamore lace bugs overwinter as an egg in woody tissue at the base of leaf buds. As the leaves of the host plant expand in the spring, reaching approximately 1.6 inches in length, the sycamore plant bug eggs begin to hatch. In a 1976-1978 study in Pennsylvania, the eggs of the sycamore plant bug hatched from late April to early May (Wheeler, 1980). The immature nymphs will begin feeding on the leaves of their host, on both leaf surfaces (upper and lower). However, Wheeler (1980) observed that feeding occurs primarily on the lower leaf surface and Dodge (1943) reported more feeding on the upper leaf surface. The nymph life stage is smaller than the adult, wingless, and yellowish brown in color. At least 5 nymphal instars occur. By late May into early June, the nymphs will have matured into adults based on records from Pennsylvania. Adults are approximately 1/4 inch in length, yellow/brown in color, with whitish wings. Adult males outnumber adult females until early June and die sooner, so that by early July the population is almost entirely female. Until mid-July, the adult life stage is present. However, the latest collection of females in PA occurred on August 10 or 12 in Wheeler (1980). A single generation occurs per year. The sycamore plant bug is known to the Northeastern United States and parts of Canada. The damage to the leaf from the sycamore plant bug may sometimes be confused for that of the sycamore leaf beetle larvae and adults. The sycamore leaf beetle (Neochlamisus platani) will chew larger irregular holes in the leaves than the feeding damage caused by the sycamore plant bug.
The feeding of the sycamore plant bug pierces host plant leaf tissues and causes chlorotic areas to develop. As time progresses through the season, these spots become browned and may even drop from the leaf. This leaves behind a very ragged and tattered appearance to the leaf. If very young, developing leaves are fed upon by these insects they may become mottled in appearance as well as distorted. Wheeler (1980) observed that relatively small populations of this insect can cause noticeable damage to London plane trees in both street and nursery plantings. Nymphs may also be found on developing fruit heads of their hosts. The damage the sycamore plant bug causes to its hosts is atypical for similar species of insect. Dodge (1943) and Pirone (1978) hypothesize that this insect may inject a poisonous substance into the leaves of the host plant from the insect's salivary glands, however further scientific study to prove this hypothesis is needed.
Visually monitor host plant leaves for sycamore plant bug as soon as they expand to 1.6 inches in length in the spring. Very small numbers of individuals (1-15 per approximately 1 foot section of 20 branches sampled) may be all that is needed to damage the host plant noticeably (Wheeler, 1980). This is a very small number of individuals in comparison to the number of insects it takes to damage for example honeylocust trees from very similar branch samples (ex. 2,000 honelocust plant bugs, Diaphnocoris chlorionis, from 8 one foot branches on honeylocust). Discoloration of host plant leaves may become more apparent as the population of nymphs reaches the 3rd and 5th instar. By late May, it may become severe. By late June, the characteristic tattered appearance to the leaves may be visible.
If the tree is small enough, the nymphs may be syringed from the host plant with a strong jet of water from a hose. Often, however, cultural management options for these insects are impractical. The best cultural management option is therefore prevention of additional stressors on the host plant which, in combination with sycamore plant bug feeding, may exacerbate the impact of this insect. Typically, on otherwise healthy hosts without additional biotic or abiotic stressors, the damage from this insect is only aesthetic and can be tolerated. As always, managing host plants to improve their overall health and vigor can reduce the impact of an insect pest. High winds may be capable of blowing a majority of the insects from their host plant (Wheeler, 1980).
None noted at this time.
Acephate (NL)
Acetamprid (L)
Beauveria bassiana (NL)
Bifenthrin (NL)
Carbaryl (L)
Chlorpyrifos (N)
Chromobacterium subtsugae (NL)
Clothianidin (NL)
Cyantraniliprole (NL)
Cyfluthrin (NL)
Deltamethrin (L)
Dinotefuran (NL)
Flonicamid+cyclaniliprole (N)
Tau-fluvalinate (NL)
Gamma-cyhalothrin (L)
Horticultural oil (L)
Imidacloprid (L)
Insecticidal soap (NL)
Isaria (paecilomyces) fumosoroseus (NL)
Lambda-cyhalothrin (L)
Malathion (L)
Neem oil (NL)
Permethrin (L)
Spinetoram+sulfoxaflor (N)
Active ingredients that may be applied systemically include: acephate (injection), acetamprid (injection), clothianidin (soil drench), cyantraniliprole (soil drench, soil injection), dinotefuran (soil drench), imidacloprid (soil drench), and neem oil (soil drench).
Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.
Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.
