Washington State University
Mount Vernon NWREC
Mount Vernon, WA 98273
Current bamboo aphid, Takecallis arundicolens (Clarke), control recommendations can be improved by including new chemistries and expanding the comparative data to provide a more clear management approach. Bioassays were conducted in the laboratory on 30 September 2005. Unrolled young leaves, with varying densities of bamboo aphids, were removed from infested green sulcus bamboo, Phyllostachys aureosulcata F. ‘alata,’ and placed in Petri dishes on cotton dampened with de-ionized water. Each Petri dish contained five replicates. Bioassays were performed with a Precision Spray Tower operated at 40 psi. Each Petri dish was treated with one of eight chemicals (Table 1) at the rate of one ml/Petri dish. Treatments were evaluated one and two days following application. Live and dead aphids were counted (based on probing to check for movement) and percent mortality determined.
This test provides a useful comparison between three neonicotinoids, Provado (imidacloprid), Assail (acetamiprid), and Actara (thiamethoxam). All three products provided excellent control of bamboo aphid at 1 DAT. In addition, an IGR, Aza-Direct (azadiractin), was also tested, providing another option for bamboo growers.
Actara (thiamethoxam), Assail (acetamiprid), Malathion, Provado (imidacloprid) and Talstar (bifenthrin), exhibited complete control against bamboo aphids, 24 hours post-treatment. Sanmite (pyridaben) was 71% effective controlling spider mites 24 hours following treatment. Fulfill (pymetrazine) and Aza-Direct were the least effective at 1 DAT with only 59% and 61% control. Neither Fulfill (pymetrozine) nor Aza-Direct exhibit a “knockdown” effect due to general toxicity or paralysis. Instead, these two biorationals exhibit unique modes of action. Fulfill affected aphids stop feeding within a few hours and die of starvation, while Aza-Direct interferes with the molting process. Fulfill exhibited the most dramatic increase in mortality rate in a 24 hours period, from 59% at 1 DAT, to 91% at 2 DAT. It is speculated that the level of aphid suppression for both aphicides would be comparable to that of other compounds if evaluated at 3-5 DAT. Sanmite and Talstar exhibited cross-activity against both bamboo aphids and bamboo spider mites, with Talstar performing the best.
|Treatment||Product (amt/100 gal)||Percent mortality|
|Aza-Direct||24 fl oz||61||63|
|Fulfill 50 WG||2.75 oz||59||91|
|Provado 1.8F||3.75 fl oz||99||100|
|Talstar F||20 fl oz||98||99|
|Assail 70WP||22 oz||100|
|Actara 25WG||4 oz||100|
|Sanmite 75WP||39 oz||71||80|
|Malathion 8F||32 fl oz||100|