Pini Dunner B.A (Hons), formerly rabbi of London's Saatchi Synagogue, is an avid collector of polemical and controversial Hebraica, with a very large, diverse private collection of such material. Many items in his collection are unknown and unrecorded, and relate to long forgotten, obscure controversies.
This is Pini Dunner's third post at the Seforim blog. His first post, "Mercaz Agudat Ha-Rabbanim Be-Lita, Kovno, 1931," is available here; his second post, "Unknown Picture of the late Lubavitcher Rebbe, c.1930s," is available here.
For background on the controversy over Corfu etrogim, see Yosef Salomon, "The Controversies Regarding the Corfu and Eretz Yisrael Etrogim 1875-1891," Zion 65.1 (2000): 75-106; Yosef Salomon, "The Controversy Regarding the Corfu Etrogim and its Historical Significance," AJS Review 25 (2000-2001): 1-25; Yitzhak Refael, "Corfu Etrogim and Eretz Yisrael Etrogim," Sheragi 2 (1985), 84-90; Dan Porat, "The Controversy over Israeli Etrogim from 1875-1889," (MA thesis, Hebrew University of Jerusalem, 1993); H. Hamel, "R. Yosef Zehariah Stern's Position in the Corfu Etrogim Controversy," in Sefer Refael (Jerusalem, 2000), 242-251. For a brief discussion about the broadsides authored by R. Gershon Henoch Leiner and his son R. Mordechai Joseph Eliezer Leiner of Izbica-Radzin that were posted throughout Poland, see Pearl Preschel, "The Jews of Corfu," (PhD dissertation, New York University, 1984), 111-112, 113-114, 159.
Regarding the Russian text at the bottom of the broadside, the following is a translation that was obligatory to appear on all non-Russian books:
Condemnation by M.I.Leiner of those rabbis, which, as the revenge for the dwellers of the Greek islands for the disturbances on the island of Corfu, prohibited the paradise apples originating from those islands for using them in the religious ceremony of the holiday of Sukkot.
Included is a protest letter by the rabbi of Corfu about the matter.
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Permitted by the censorship, Warsaw, 15 July 1891 — printing of M.I. Galter Nalevki [St.] 23.
Handbill Defending the Use of the Corfu Etrogim authored by R. Mordechai Joseph Eliezer Leiner of Izbica-Radzin  published in Izbica, July 1891
This broadside contains a vigourous and impassioned defence of the practice of using etrogim from Corfu in preference to those from Eretz Yisrael. For centuries the most prized etrogim used by Jews of all communities were those grown in Corfu, and the etrog industry on the island was a mainstay of the local economy. It was said that the etrogim grown in Corfu traced their origins to those used during the second temple period, and were therefore of the most reliable pedigree. The untainted pedigree of an etrog is of primary importance, and as a result Corfu etrogim were highly sought after, making them expensive. Furthermore, the owners of the orchards – many of them non-Jews – fiercely guarded their monopolies, and were extremely careful that their etrogim were of unimpeachable pedigree.
This broadside was issued as a result of the drift away from using etrogim grown on the island of Corfu in the late nineteenth century. Initially this began with a ban on their use that was issued c.1875 and that had its roots in the growing suspicion that Corfu etrogim were no longer reliable in their pedigree and that growers had secretly begun grafting them with other citrus fruits to boost the numbers of fruit that were fit for use, and in addition would be outstanding in their appearance, boosting their value.
Then in 1891, the year of this broadside, the ban against Corfu etrogim was strengthened as a result of the terrible anti-semitism on the island that had led to a vicious blood libel. Jewish communities formerly loyal to Corfu etrogim switched their allegiances to the ever expanding etrogim market of Eretz Yisrael and it was this that R. Leiner was trying to prevent. R. Leiner (1877-1929) was the scion of the Izbica/Radzyn dynasty and in this broadside he quotes his recently departed father, R. Gershon Henoch (1839-1891), the famous 'Baal ha-Techeilet', as saying that there were no better and more kosher etrogim than those that grew in Corfu. He added that those grown in Eretz Yisrael were probably unfit for use and, furthermore, the excuse that they provided income for poor farmers there was utterly inappropriate in light of their unfitness. He added that the chief rabbi of Corfu, R. Elisha mi-Pano, had written to him to say that the ban effected against Corfu etrogim (the annual market for etrogim was of major economic significance to the small island) as a result of the blood libel was making matters worse for the Jews of Corfu.
Despite attemps by R. Leiner and other advocates of Corfu etrogim, the Corfu etrog business went into terminal decline. By the early twentieth century the rival industry in Eretz Yisrael had grabbed the overwhelming majority of the etrogim market, and with the upheaval of the two world wars, and following the creation of the State of Israel, Corfu etrogim disappeared completely from the scene.
Recently, I understand, there has been some effort to revive the fortunes of the Corfu etrog. It would seem that an emissary of R. David Twersky of New Square annually acquires etrogim from Corfu for R. Twersky to use on sukkot. No doubt this action is motivated by R. Twersky's well-known desire to strictly follow the customs of his illustrious forebears who, in the years when the etrogim controversy raged, were devotees of Corfu etrogim over their Eretz Yisrael counterparts. Nevertheless, as any etrog grower will tell you, once an etrog orchard has been abandoned, any fruit that emerge from it in the years that follow, especially if many years pass, no longer have a chezkat kashrut, and more than likely they are murkavim. It would be interesting to know if R. Twersky makes a bracha on these questionable etrogim, or if he first uses an etrog of reliable pedigree and then switches to the murkav simply for sentimental purposes.